Aspiration monitoring system and method

ABSTRACT

A system for real time monitoring of catheter aspiration includes a pressure sensor configured for placement in fluid communication with a lumen which at least partially includes an aspiration lumen of a catheter, the aspiration lumen configured to couple to a vacuum source, a measurement device coupled to the pressure sensor and configured for measuring deviations in fluid pressure, and a communication device coupled to the measurement device and configured to generate a continuous signal which is proportional to measured fluid pressure.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/245,124, filed Aug. 23, 2016, now U.S. Pat. No. 10,702,292, whichclaims the benefit of priority to U.S. Provisional Application No.62/211,637, filed on Aug. 28, 2015, U.S. Provisional Application No.62/213,385, filed on Sep. 2, 2015, U.S. Provisional Application No.62/239,795, filed on Oct. 9, 2015, U.S. Provisional Application No.62/239,953, filed on Oct. 11, 2015, and U.S. Provisional Application No.62/318,388, filed on Apr. 5, 2016, all of which are herein incorporatedby reference in their entirety for all purposes. Priority is claimedpursuant to 35 U.S.C. § 120 and 35 U.S.C. § 119

BACKGROUND OF THE INVENTION Field of the Invention

The field of the invention generally relates to an aspiration system forremoving, by aspiration, undesired matter such as a thrombus from afluid carrying cavity, duct, or lumen of the body, such as a bloodvessel.

Description of the Related Art

A treatment method for removing undesired matter such as thrombus from ablood vessel of a patient involves use of an aspiration catheter havingelongate shaft formed with an aspiration lumen extending therein. Anaspiration catheter may also include a guidewire lumen for placement ofa guidewire, which is used to guide the aspiration catheter to a targetsite in the body. By applying a vacuum (i.e. negative pressure) to aproximal end of the aspiration lumen, for example, with a syringe havinga hub that is connected to the proximal end of the aspiration catheter,the matter can be aspirated into an aspiration port at the distal end ofthe aspiration catheter, into the aspiration lumen, and thus be removedfrom the patient.

SUMMARY OF THE INVENTION

In one embodiment, a system for real time monitoring of catheteraspiration includes a pressure sensor configured for placement in fluidcommunication with a lumen which at least partially includes anaspiration lumen of a catheter, the aspiration lumen configured tocouple to a vacuum source, a measurement device coupled to the pressuresensor and configured for measuring deviations in fluid pressure, and acommunication device coupled to the measurement device and configured togenerate a continuous signal which is proportional to measured fluidpressure.

In another embodiment, a system for real time monitoring of catheteraspiration includes a pressure sensor configured for placement in fluidcommunication with an aspiration lumen of a catheter, the aspirationlumen configured to couple to a vacuum source, a measurement devicecoupled to the pressure sensor and configured for measuring variationsin fluid pressure, and a communication device coupled to the measurementdevice and configured to generate a continuous signal which variesproportionally as a result of variation in fluid pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a system for aspiration according to anembodiment of the present disclosure.

FIG. 2A is a view of an aspiration monitoring system according to afirst embodiment of the present disclosure.

FIG. 2B is a view of an aspiration monitoring system according to asecond embodiment of the present disclosure.

FIG. 3 is a view of an aspiration monitoring system according to a thirdembodiment of the present disclosure.

FIG. 4A is a sectional view of an aspiration catheter in a blood vesselprior to contact with a thrombus.

FIG. 4B is a sectional view of an aspiration catheter in a blood vesselupon contact with a thrombus.

FIG. 4C is a sectional view of an aspiration catheter during a loss ofvacuum.

FIG. 4D is a sectional view of thrombi being aspirated through anaspiration catheter.

FIG. 5A is a graphic representation of pressure vs. time for thecondition of FIG. 4A.

FIG. 5B is a graphic representation of pressure vs. time for thecondition of FIG. 4B.

FIG. 5C is a graphic representation of pressure vs. time for thecondition of FIG. 4C.

FIG. 5D is a graphic representation of pressure vs. time for thecondition of FIG. 4D.

FIG. 6 is a graphic representation of pressure and an output soundamplitude vs. time for an embodiment of an aspiration monitoring system.

FIG. 7 is a graphic representation of pressure and an output soundamplitude vs. time for an embodiment of an aspiration monitoring system.

FIG. 8 is a graphic representation of pressure and an output soundfrequency vs. time for an embodiment of an aspiration monitoring system.

FIG. 9 is a graphic representation of pressure and an output of soundfrequency vs. time for an embodiment of an aspiration monitoring system.

FIG. 10 is a plan view of a system for aspiration according to anotherembodiment of the present disclosure.

FIG. 11 is a plan view of a system for aspiration according to anotherembodiment of the present disclosure.

FIG. 12 is a detailed view of an aspiration monitoring system of thesystem for aspiration of FIG. 11 .

FIG. 13 is a plan view of a system for aspiration according to anotherembodiment of the present disclosure.

FIG. 14 is a detailed view of an aspiration monitoring system of thesystem for aspiration of FIG. 13 .

FIG. 15 is a diagrammatic view of a system for aspirating thrombusaccording to an embodiment of the present disclosure.

FIG. 16 is a diagrammatic view showing more detail of the proximalportion of the system for aspirating thrombus of FIG. 15 .

FIG. 17 is a diagrammatic view of the distal end portion of the systemfor aspirating thrombus of FIG. 15 .

FIG. 18 is a plan view of a portion of a multi-purpose system accordingto an embodiment of the present disclosure.

FIG. 19 is a perspective view of a proximal portion of the multi-purposesystem of FIG. 18 .

FIG. 20 is a plan view of a portion of a multi-purpose system accordingto an embodiment of the present disclosure.

FIG. 21 is a detail view of the distal end of a multi-purpose catheterof the multi-purpose system of FIG. 20 .

FIG. 22 is a perspective view of a proximal portion of the multi-purposesystem of FIG. 20 .

FIG. 23 is a plan view of a proximal portion of the multi-purpose systemof FIG. 20 .

FIG. 24 is a perspective view of a portion of the multi-purpose systemof FIG. 20 .

FIG. 25 is a plan view of an aspiration catheter according to anembodiment of the present disclosure.

FIG. 26 is a plan view of a tubing set according to an embodiment of thepresent disclosure.

FIG. 27 is a plan view of a stopcock according to an embodiment of thepresent disclosure.

FIG. 28 is a plan view of a stopcock according to an embodiment of thepresent disclosure.

FIG. 29 is a plan view of a vacuum source according to an embodiment ofthe present disclosure.

FIG. 30 is a plan view of an aspiration system according to anembodiment of the present disclosure.

FIG. 31 is a plan view of an aspiration system according to anembodiment of the present disclosure.

FIG. 32 is a plan view of an aspiration system according to anembodiment of the present disclosure.

FIG. 33 is a plan view of an aspiration system according to anembodiment of the present disclosure.

FIG. 34 is a partial sectional view of an embodiment of a salineinjection aspiration (thrombectomy) catheter according to an embodimentof the present disclosure, with a guidewire in place.

FIG. 35 is a plan view of the proximal end of a guiding catheter with anaspiration catheter placed therein.

FIG. 36 is a perspective view of a syringe with a rotatable elementaccording to an embodiment of the present disclosure.

FIG. 37 is a perspective view of an aspiration system utilizing onemodification of the syringe of FIG. 36 according to an embodiment of thepresent disclosure.

FIG. 38 is a side view of aspiration system utilizing anothermodification of the syringe of FIG. 36 according to an embodiment of thepresent disclosure.

FIG. 39 is a plan view of an aspiration system according to anotherembodiment of the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The present disclosure relates to aspiration catheter systems andmonitoring, warning and communication systems for aspiration cathetersystems. Clogging of aspiration catheters, for example by large piecesof thrombus, is a common concern for users. Techniques to avoidclogging/choking of material within the catheter often involve rapidly,aggressively advancing the aspiration catheter or gently plucking atedges of a thrombus to insure only small pieces or portions areintroduced at a time, pieces which are small enough to not clog orocclude the aspiration lumen. When a device becomes clogged during use,the potential for inadvertent dislodgment of thrombus downstreamincreases; this is referred to as distal embolism. As aspirationprocedures of this type are often used in highly technical emergentsettings, early clog detection of the aspiration catheter for the userduring aspiration can contribute to the success of the procedure andclinical outcome. Some sources have reported that up to 50% ofaspiration catheters used get clogged during use.

The user may have difficulty determining whether there is a vacuum inthe system or not. For example, the user may have difficulty determiningwhether the vacuum has been applied or not (e.g., the vacuum source hasbeen turned on or off). Additionally, the user may have difficultydetermining whether there has been a loss of vacuum in the system, forexample because of the syringe (or other vacuum source) being full offluid or because of a leak in the system. Blood is relatively opaque andcan coat the wall of the syringe, thus making it difficult to determinewhen the syringe becomes full. This makes it difficult to determinewhether sufficient vacuum is being applied to the aspiration catheter.The vacuum level may change to an unacceptable level even before thesyringe becomes full. Extension tubing or other tubing may also cause aloss in vacuum in the system. Certain tubing kinks may be difficult fora user to see or identify. It is also difficult to determine whetherthere is an air leak in the system, which can be another cause for aloss of vacuum even before the syringe becomes full of the aspiratedfluid.

During the aspiration of thrombus with an aspiration catheter, it isdifficult to identify when thrombus is actively being aspirated, or whenonly blood is being aspirated. Typically, it is desired to not aspiratesizable quantities of normal blood from blood vessels, because of theimportance of maintaining normal blood volume and blood pressure.However, when tracking the tip of an aspiration catheter in proximity toa thrombus, it is difficult to know whether the aspiration catheter hasactively engaged a thrombus, whether it has aspirated at least a portionof the thrombus, or whether it is not engaged with the thrombus, and isonly aspirating blood. Though some aspiration catheters, such as thoseused in the peripheral blood vessels or in an arterio-venous fistula,may be around 50 cm or even less, the tip of an aspiration catheter mayin same cases be more than 90 cm from the hands of the user, or as muchas 135 cm from the hands of the user, or in some cases as much as 150cm, and the particular status of vacuum at the tip of the catheter isoften not known by the user. A user may thus be essentially plunging acatheter blindly without significant, usable sensory feedback. Thecatheter may have an outer diameter up to or even greater than 6 French,and may be as high as 10 French or greater. The increased catheter outerdiameter can cause some concern of potential trauma inside a bloodvessel. The use of aspiration catheters can therefore be inefficient,and cause more blood removal than desired, causing a user to minimizethe length of the therapy and in severe cases necessitating bloodtransfusion. An increased volume of normal blood being aspirated alsomeans that the vacuum source (e.g. syringe) will fill in a shorteramount of time, thus requiring more frequent replacement of the vacuumsource. Distal embolism may occur if the vacuum pressure is notsufficient, and yet the user is not aware.

In some cases, a syringe that is completely or mostly full or bloodand/or thrombus may continue to be used, though in this state, there isnot sufficient pressure to effectively aspirate thrombus or unwantedmaterial, thus causing inefficient use of time, and lengthening theprocedure. In some cases, the user may not realize the plunger of thesyringe has mistakenly not been pulled back (to evacuate the syringe).In some cases, the syringe itself may be defective, and a proper vacuummay not be achieved, without the user being aware. In some cases, kinkedtubing, lines, or catheters may go unnoticed, because of bad visibilityin a procedural laboratory, or simply from the extent of concurrentactivities being performed. In many cases, the user's eyes are orientedor focused on a monitor, for example a fluoroscopic monitor or otherimaging monitor, or a monitor with patient vital data. Though the usermay be able to view flow through transparent or partially transparentlumens (such as extension tubing), in dim lighting with intermittentviewing, it is difficult for the user's mind to process flow of anopaque liquid (such as blood/thrombus). Even in good lighting with afocused eye, the movement of fluid through extension tubing may notpresent an accurate picture of the aspiration status, as the visual floweffect may be delayed in relation to the applied vacuum. More than onemedical device personnel may be sharing sensory information with eachother to attempt to build a current status in each other's minds of theaspiration procedure. When a user relies on another's interpretation,especially when either are multitasking, a false sense of the status mayoccur. A syringe attached to the aspiration catheter may cause kinking,for example, if placed on an uneven surface. The distal opening in anaspiration lumen of an aspiration catheter may be prone to aspiratingdirectly against the wall of a blood vessel, thus being temporarilystuck against the vessel wall, and stopping flow throughout theaspiration lumen. In some cases, a vacuum that is too large may beaccidentally or inappropriately applied to the aspiration lumen of theaspiration catheter, limiting effectiveness (for example, if it causesthe walls surrounding the aspiration lumen to collapse and thus, cut offthe significantly decrease the flow through the aspiration lumen). Thesyringes which are sometimes used as a vacuum source to connect to anaspiration lumen of an aspiration catheter may malfunction, and not befully actuated/evacuated. But, even when the syringe is functioningcorrectly, it will tend to fill up at difficult to predict moments, andthus commonly have periods with no applied vacuum. In the cases whereina portion of clot/thrombus is being aspirated through the aspirationlumen, a significant pressure drop may occur at the current position ofthe thrombus, and thus, a sufficient vacuum may only exist from theproximal end of the aspiration lumen and distally up to the point of thethrombus. Thus, an insufficient vacuum may exist at the distal end ofthe aspiration lumen, e.g., at the distal end of the aspirationcatheter. The same situation may occur if there is an actual clog atsome intermediate point within the aspiration lumen. In either of theseconditions, because of the insufficient vacuum at the distal end of theaspiration lumen, there may be a risk of thrombus or emboli being sentdistally in the vasculature, which may cause occlusion, stroke,pulmonary embolism, or other disorders, depending upon the location ofthe intervention or procedure being performed. With current apparatusand techniques, these situations are very difficult to detect when theyoccur. It has been estimated that in as many as 50% of thrombusaspiration procedures, some sort of failure occurs.

An aspiration system 2 is illustrated in FIG. 1 and is configured toallow real time monitoring of catheter aspiration. The aspiration system2 comprises an aspiration catheter 4, a vacuum source 6, a valve 8,extension tubing 10, and an aspiration monitoring system 48 including anin-line pressure transducer 12. The aspiration catheter 4 has a proximalend 14 and a distal end 16 and an aspiration lumen 18 extending from theproximal end 14 to the distal end 16. The aspiration lumen 18 may besized for aspiration of thrombus, and in some embodiments may have aninner diameter of between about 0.38 millimeter (0.015 inches) and about2.54 millimeters (0.100 inches). The aspiration catheter 4 includes ahub 20 at its proximal end which may include a female luer connector 22.The aspiration lumen 18 at the distal end 16 of the aspiration catheter4 may include an angled orifice 24, which aids in the tracking throughtortuous or occluded vasculature. In some embodiments, a guidewire lumen26 is coupled to the distal end 16 of the aspiration catheter 4, and isconfigured to track over a guidewire 28. The vacuum source 6 maycomprise a syringe, and may be sized between 5 ml and 100 ml, or between20 ml and 60. The vacuum source 6 may comprise a VacLok® syringe, madeby Merit Medical, South Jordan, Utah. The vacuum source 6 may include abarrel 30 and plunger 32, with a lock 34 which is configured to retainthe plunger 32 in position in relation to the barrel 30, for example,when the plunger 32 is pulled back in direction D to create a negativepressure (vacuum) inside the barrel 30. In some embodiments, the vacuumsource 6 may comprise any other type of evacuatable reservoir, or maycomprise a vacuum pump. The vacuum source 6 is connected to theaspiration lumen 18 of the aspiration catheter 4 via the extensiontubing 10 and the valve 8. In some embodiments, the vacuum source 6 maybe connected directly to the aspiration lumen 18 of the aspirationcatheter 4. Male luer connectors 36 and female luer connectors 38 areindicated in FIG. 1 . The valve 8 may be a standard two-way stopcock, asillustrated.

The pressure transducer 12 of the aspiration monitoring system 48 isconfigured to be fluidly coupled between the vacuum source 6 and theaspiration catheter 4. In FIG. 2A, the aspiration monitoring system 48is illustrated as a self-contained device of a first embodiment. Thepressure transducer 12 comprises a housing 40 having a cavity 42extending between a first port 44 and a second port 46. In someembodiments, the first port 44 comprises a female luer and the secondport 46 comprises a male luer. In some embodiments, the first port 44comprises a female luer lock and the second port 46 comprises a maleluer lock, each of which is attachable to and detachable from acorresponding luer lock of the opposite gender. The first port 44 isconfigured to be coupled to the vacuum source 6, either directly, orwith the valve 8 and/or extension tubing 10 connected in between. Thesecond port 46 is configured to be coupled to the aspiration lumen 18 ofthe aspiration catheter 4, for example, by coupling the second port 46directly or indirectly to the hub 20 of the aspiration catheter 4. Whenthe aspiration system 2 is used to aspirate body fluids and/ormaterials, for example blood and/or thrombus, the body fluids and/ormaterials are aspirated through the aspiration lumen 18 of theaspiration catheter from the angled orifice 24 at the distal end 16 tothe female luer connector 22 at the proximal end 14, then pass throughthe second port 46 of the pressure transducer 12 first, through thecavity 42, and then through the first port 44. Depending on the amountof amount of vacuum (negative pressure) applied by the vacuum source 6,and the amount of flow resistance and resulting pressure drop along theaspiration system 2, the pressure within the cavity 42 will vary. Forexample, a more viscous fluid like blood, or a fluid having solid,semi-solid, or gel-like particles or portions, will cause more flowresistance through the relatively small aspiration lumen 18 of theaspiration catheter 4 than would water or normal saline solution. Thusthe pressure within the cavity 42 of the pressure transducer 12 willdecrease (the amount of vacuum will increase) as the flow resistance inthe aspiration lumen 18 increases.

For definition purposes, when speaking of the amount of vacuum, apressure of, for example, −15,000 pascal (−2.18 pounds per square inch,or psi) is a “larger vacuum” than −10,000 pascal (−1.45 psi).Additionally, −15,000 pascal is a “lower pressure” than −10,000 pascal.Furthermore, −15,000 pascal has a larger “absolute vacuum pressure” thandoes −10,000 pascal, because the absolute value of −15,000 is largerthan the absolute value of −10,000. In FIG. 2A, a vacuum sensor 50 isdisposed within the cavity 42 of the housing 40 and is in fluidcommunication with fluid that passes through the cavity 42. The vacuumsensor 50 may be a standard pressure sensor or transducer, including apressure sensor designed primarily for measuring positive pressure. Itmay use any type of pressure sensing technology known in the art,including MEMS Technology. In some embodiments, the vacuum sensor 50 isconfigured for highest accuracy and/or precision within the range ofpressures between about 0 pascal to about −101,325 pascal (−14.70 psi),or between about −45,000 pascal (−6.53 psi) and about −90,000 pascal(−13.05 psi), or between about −83,737 pascal (−12 psi) and about−96,527 pascal (−14 psi). In some embodiments, the power requirement forthe vacuum sensor may range from 2.5 volts DC to 10 volts DC. In someembodiments, the vacuum sensor 50 may be an analog gauge with an outputvoltage. In the self-contained embodiment of the FIG. 2A, the vacuumsensor 50 is powered by one or more battery 52. Based on the powerrequirements of the vacuum sensor 50, and the power requirements ofother components of the aspiration monitoring system 48 describedherein, in some embodiments the one or more battery 52 may range between1.5 volts and nine volts. Also contained within the housing is ameasurement device 54, which in some embodiments may comprise amicroprocessor. The measurement device 54 is coupled to the vacuumsensor 50 and receives signals from the vacuum sensor 50 indicative ofreal time measured pressure. In some embodiments, the measurement device54 includes a memory module 56 in which information is stored that maybe used by the measurement device 54, for example, in calculations.Information may include, for example, an array of one or more pressurevalues. In some embodiments, the array of one or more pressure valuesmay be correlated with one or more different corresponding system modelsor catheter models. The vacuum sensor 50 may be used in some cases fordetecting the presence or amount of vacuum alone, for the purpose ofmonitoring whether the vacuum source 6 (e.g., syringe) is significantlyfull, and thus needs to be changed. The vacuum sensor 50 may be used insome cases for detecting whether there is a vacuum in the system of not.For example, whether the vacuum has been applied or not (e.g., thevacuum source has been turned on or off).

One or more communication devices 58 a, 58 b, 58 c are included withinthe aspiration monitoring system 48 and are coupled to the measurementdevice 54. Each of the one or more communication devices 58 a-c areconfigured to generate a type of alert comprising an alert signal 60a-c, in response at least in part to activity and output of themeasurement device 54. In some embodiments, the communication device 58a may include one or more LEDs (light emitting diodes) configured togenerate a visible alert via a visible alert signal 60 a, such as lightthat is continuously illuminated, or is illuminated in a blinkingpattern. In some embodiments, the LEDs may be oriented on multiple sidesof the communication device 58 a, so that they may be easily seen from avariety of different locations. In some embodiments, lights other thanLEDs may be used. Light pipes or other lighting conduits may also beincorporated in embodiments, to further place visual indicators atmultiple locations and/or orientations. In some embodiments, thecommunication device 58 b may include one or more vibration generatorsconfigured to generate a tactile alert via a tactile alert signal 60 b,which may include, but is not limited to, vibration or heat. In someembodiments, the vibration device may be similar to a video gamecontroller. In some embodiments, the vibration generator may comprise apiezoelectric device which is configured to vibrate when a voltage isapplied. In some embodiments, the communication device 58 c may includeone or more sound generating devices configured to generate an audiblealert via an audible alert signal 60 c, such as a continuous noise, or arepeating noise. The communication device 58 c in some embodiments maycomprise a loudspeaker for generation of any variety of sounds, at anyvariety of frequencies (Hz) or sound pressures (dB) within the humanaudible range and/or human tolerance range. The communication device 58c may even be configured to generate sounds that are outside the humanaudible range in embodiments wherein the signal is intended to be feltas a vibration or other tactile sensation, instead of an audiblesensation. In some embodiments, the sound generating device may comprisea buzzer which is configured to sound one or more audible pitches when avoltage is applied. In some embodiments a piezoelectric device, such asthat described in relation to the communication device 58 b may alsoserve as a sound generating device, included as communication device 58c. The alert signal 60 a-c can at times serve as a “wake up” alarm forthe user, in cases where the user has become too focused on otherfactors during the procedure.

A user of an aspiration system 2 may desire to be notified of severalconditions which may occur during use of the aspiration system 2. Thesepotential conditions include, but are not limited to clogging, a loss ofvacuum due to filling of the vacuum source 6 and or a breach, break orpuncture in the aspiration system 2, and the engagement or aspiration ofnon-fluid, solid or semi-solid material such as thrombus. The aspirationmonitoring system 48 of FIG. 2A is configured to alert users of anaspiration system 2 about real time status of the aspiration system 2,including operational conditions, which include: whether vacuum is beingapplied or not; flow conditions, which include whether a thrombus isengaged, whether a thrombus is being actively aspirated, whether thesystem is leaking air, whether the system is clogged, whether the vacuumsource 6 is full and/or needs to be changed; or other potential set upissues. The real time feedback provided frees a user or operator fromthe need of excessive personal monitoring of the vacuum source 6,extension tubing 10, or other portions of the aspiration system 2, forimproper or undesired flow or operation conditions, and thus allows theuser to focus more attention on the patient being treated. The user iskept aware of whether a clot is being aspirated or has been aspirated,or whether there is a clog. Additionally, the user is kept aware ofwhether there is too large an amount of blood being removed from thepatient, or whether there are fault conditions like system leak ortubing kink. A tubing kink distal to the vacuum sensor 50 may beidentified (for example by an increase in measured vacuum) and a tubingkink proximal to the vacuum sensor 50 may be identified (for example, bya loss or degradation of vacuum). In some cases, the user may attempt tooperate the catheter with a vacuum source 6 that is already full (andthus has no significant vacuum). In some cases, a user may even forgetto open the valve 8 to begin suction, but the aspiration monitoringsystem, 48 can also identify that the system is not yet functioning, andcommunicate a list of potential errors or specific errors (for theparticular pressure waveform measured). By having the real-timeawareness of the many factors related to the operating status, theprocedure is made safer, the time of the procedure may be reduced, andblood loss may be reduced.

The pressure transducer 12 of the aspiration monitoring system 48 isconfigured to continuously measure and monitor the absolute pressureamplitude within the closed system of the aspiration system 2, and alsois configured to measure and monitor the relative pressure over time todetect noteworthy flow changes within the flow circuit of the aspirationsystem 2. Some changes are discernible via absolute pressuremeasurement, while more subtle pressure deflections may be compared to astored library in memory. Noteworthy conditions may be signaled to theuser when appropriate. In some embodiments, the unfiltered signal may beamplified by an amplifier and filtered by a filter, for example, toincrease the signal-to-noise ratio. Examples of the (background) noise57 in an unfiltered signal can be seen in FIGS. 5A-5D (labeled in FIG.5A). In some embodiments, one or more algorithms may be used, asdescribed herein, to identify particular conditions of interest.

FIG. 2B illustrates a second embodiment of an aspiration monitoringsystem 62 having a pressure transducer 12 having a vacuum sensor 50disposed within the cavity 42 of a housing 40. The vacuum sensor 50 maybe powered by at least one battery 52. In some embodiments, the pressuretransducer 12 may be reusable, and may be configured to allow chargingof the battery 52, or of a capacitor (not shown) by direct chargingmethods, or by inductive power transfer methods and devices known in theart. Unlike the aspiration monitoring system 48 of FIG. 2A, theaspiration monitoring system 62 of FIG. 2B comprises a measurementdevice 64, memory module 66, and communication device 68 which areexternal to the pressure transducer 12. A power module 72, alsoexternal, may be used to power any of the measurement device 64, memorymodule 66, or communication device 68. The communication device 68 maybe any of the communication device 58 a, 58 b, 58 c described inrelation to the aspiration monitoring system 48 of FIG. 2A, and areconfigured to product an alert via an alert signal 70. The communicationdevice 68 may be portable so that it may be positioned close to theuser.

In some embodiments, the communication device 68 may be wearable by theuser. FIG. 3 illustrates an aspiration monitoring system 78 whichincludes an antenna 80 coupled to a measurement device 76. Themeasurement device 76 is similar to the measurement device 54 of priorembodiments, except that it wirelessly sends a communication signal 84via the antenna 80 to a corresponding antenna 82 of a communicationdevice 74. In some embodiments, the communication device 74 comprises awristband which the user wears, and which may include a vibrationgenerator or heat generator. In some embodiments, the communicationdevice 74 comprises an audio speaker which may be attached to equipmentor even to the patient or user. In some embodiments, the communicationdevice 74 comprises an audio speaker on an earpiece or earbud that theuser may wear. In some embodiments, Bluetooth® communication technologymay be used. The real time feedback supplied by the aspirationmonitoring system 62 may decrease the time that the aspiration system 2is actively aspirating without being engaged with a thrombus, thusminimizing the amount of non-thrombotic blood lost by aspiration. Thismay be particularly beneficial in larger bore catheters, for example incatheters having a diameter of 7 French or larger. The real timefeedback may also minimize the amount of total time that catheters aretracked back-and-forth through the blood vessels, minimizing potentialdamage to the intima of the blood vessels, dissection of the bloodvessels, or distal embolization. By lowering the risk of the aspirationcatheter tip getting caught (via suction) against the blood vessel wall,the distal end of the aspiration lumen may be more aggressively designedfor optimized aspiration characteristics. The technique of using theaspiration catheter may additionally be able to be performed in a moresophisticated manner, with continual or continuous knowledge of thevacuum status. For example, a piece of thrombus may be aspirated,followed by a “chaser” of blood aspiration, followed by another piece ofthrombus, etc.

FIG. 4A illustrates the distal end 16 of an aspiration catheter 4 withina blood vessel 86 having at least one thrombus 88. The aspirationcatheter 4 is being advanced in a forward direction F, but the distalend 16 of the aspiration catheter 4 has not yet reached the proximalextremity 94 of the thrombus 88. A vacuum source 6 (FIG. 1 ) has beencoupled to the aspiration lumen 18 of the aspiration catheter 4 andactivated (i.e. the valve 8 is open) causing blood 96 to be aspiratedinto the aspiration lumen 18 (arrows A). Turning to FIG. 5A, acorresponding curve 98 is represented for the normal fluid (e.g. blood)vacuum over time for the condition of FIG. 4A. The curve 98 representsvacuum pressure over time sensed by the vacuum sensor 50 of any of theembodiments presented. No leaks are present and no thrombus is beingevacuated, and therefore the curve 98 includes a downward slope 99 whenthe vacuum source 6 increases the vacuum up (lowers the pressure) withinthe cavity 42 of the pressure transducer 12 to a relatively steadystate. The steady pressure curve 97 continues while blood 96 is beingaspirated. As the vacuum is decoupled from the aspiration lumen 18, forexample by closing the valve 8 or by detaching any two of the ports(e.g. luers), or if the vacuum source 6 fills completely with blood 96,then an upward slope 95 is measured.

The measurement device 54, 64 is configured to compare the curve 97 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, the measurementdevice 54, 64 then sends a signal to the communication device 58 a-c,74, and the communication device 58 a-c, 74 generates an appropriatealert. Communication device 58 a, for example a particular color LED,may be illuminated, or an LED may flash in a particular pattern ornumber of flashes. Communication device 58 b may create a characteristicsound, or may generate an audio message in a number of languages. Forexample, the audio message may state, “Thrombus encountered,” or “Nothrombus encountered.” A different type of sound may be used for each ofa plurality of “modes”: “Thrombus encountered,” “Actively flowing,” and“No Vacuum.” For example, a buzzing sound for “Thrombus encountered,” abeep for “No vacuum,” etc. The various characteristics of sound that maybe varied include, but are not limited to timbre, or sound quality,spectrum, envelope, duration, phase, pitch (frequency), number of sounds(repetition). Communication device 58 c may vibrate or heat in acharacteristic pattern, for example, a certain number of repetitions ora certain frequency between repetitions. The user may determine that anadditional fluoroscopic image (e.g. angiography) or other imagingmodalities may be necessary to better identify the location of thethrombus 88.

FIG. 4B illustrates the distal end 16 of an aspiration catheter 4advanced to a position such that the distal end 16 of the aspirationcatheter 4 contacts the proximal extremity 94 of the thrombus 88. Thecorresponding curve 93 in FIG. 5B represents vacuum pressure over timesensed by the vacuum sensor 50 of any of the embodiments presented. Thecurve 93 initially has a downward slope 99 followed by a steady pressurecurve 97, as in the condition of FIG. 4A, graphed in FIG. 5A, however,when the distal end 16 of the aspiration catheter 4 contacts theproximal extremity 94 of the thrombus 88, if the aspiration causes aportion of the thrombus 88 (for example a large or relatively hardportion) to enter and become trapped in the aspiration lumen 18, then aclog condition occurs. A similar condition occurs if the distal end 16of the aspiration catheter 4 is caught on the thrombus 88 by the vacuum,with virtually nothing flowing through the aspiration lumen 18. Ineither condition, the curve 93 includes a deviation (or disturbance) influid pressure 91. If the clog (or stuck condition) continues, then aflat, depressed pressure 89 is measured.

The measurement device 54, 64 is configured to compare the curve 93 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, a pre-setpressure differential ΔP₁ may be stored in the memory module 56, 66 as athreshold, whereby the measurement of a pressure difference 81 less thanthis threshold does not result in the measurement device 54, 64commanding the communication device 58 a-c, 74 to send an alert signal60 a-c, 70. In some embodiments, when the pressure difference 81 isgreater than (or greater than or equal to) the pre-set pressuredifferential ΔP₁, the measurement device 54, 64 then sends a signal tothe communication device 58 a-c, 74, and the communication device 58a-c, 74 generates an appropriate alert. Communication device 58 a, forexample a particular color LED, may be illuminated, or an LED may flashin a particular pattern or number of flashes. Communication device 58 bmay create a characteristic sound, or may generate an audio message in anumber of languages. For example, the audio message may state, “ClogCondition.” Communication device 58 c may vibrate or heat in acharacteristic pattern, for example, a certain number of repetitions ora certain frequency between repetitions. When the user realizes that theclog condition is present, the user may pull on the aspiration catheter4 and readvance it, in an attempt to contact a portion of the thrombus88 that can be aspirated. If a portion of the thrombus is clogged in theaspiration lumen 18, and repositioning of the aspiration catheter 4 doesnot produce good results, the aspiration catheter 4 can be removed andthe aspiration system 2 can be repurged, for example by a positivepressurization.

FIG. 4C illustrates the distal end 16 of the aspiration catheter 4 in ageneral situation during which a breach in the aspiration system 2 hasoccurred. For example, a break, leak, puncture, pinhole, loosening, ordisconnection may cause air to be pulled into the aspiration lumen 18 ofthe aspiration catheter 4, the cavity 42 of the pressure transducer 12,of the interior of the extension tubing 10, valve 8, or vacuum source 6.As graphed in the curve 85 of FIG. 5C, a downward slope 99 and asubsequent steady pressure curve 97 are measured, but at the point intime of the breach 87 an upward slope 83 begins.

The measurement device 54, 64 is configured to compare the curve 85 withinformation stored in the memory module 56, 66 to identify thiscondition. In some embodiments, the measurement device 54, 64 uses analgorithm to make the comparison. In some embodiments, the measurementdevice 54, 64 then sends a signal to the communication device 58 a-c,74, and the communication device 58 a-c, 74 generates an appropriatealert. Communication device 58 a, for example a particular color LED,may be illuminated, or an LED may flash in a particular pattern ornumber of flashes. Communication device 58 b may create a characteristicsound, or may generate an audio message in a number of languages. Forexample, the audio message may state, “System Leak.” Communicationdevice 58 c may vibrate or heat in a characteristic pattern, forexample, a certain number of repetitions or a certain frequency betweenrepetitions. Upon receiving the alert, the user will check thecomponents of the aspiration system 2 and either fix the breach orreplace one or more of the components of the aspiration system 2. Forexample, in some cases, the communication device 58 a-c, 74 may alertthe user when the measurement device 54, 64 confirms a loss of vacuum,allowing the user to change or recharge the vacuum source 6, which hasbecome depleted (e.g. by filling with blood and/or thrombus).

FIG. 4D illustrates the distal end 16 of the aspiration catheter 4during the successful aspiration of pieces or portions 90 of thethrombus 88. In some cases, the pieces or portions 90 may follow atortuous path 92, due to disturbances or collisions with the inner wallof the aspiration lumen 18 while being pulled through the aspirationlumen 18. In some cases, the pieces or portions 90 may catch and slipwithin the inner wall of the aspiration lumen 18, for example, do tovariance of the inner diameter of the aspiration lumen 18 along thelength. Either of these situations can cause a corresponding series ofincreases and decreases in the pressure being sensed by the pressuretransducer 12, while the pieces or portions 90 are traveling through theaspiration lumen 18. As graphed in the curve 79 of FIG. 5D, a downwardslope 99 and a subsequent steady pressure curve 97 are measured, but asthe pieces or portions 90 of thrombus 88 travel down the aspirationlumen 18 of the aspiration catheter 4, a deviation 77 of fluid pressurecomprising a one or more decreases and increases in pressure (increasesand decreases in vacuum pressure) is measured. As the pieces or portions90 of thrombus 88 exit the proximal end of the aspiration lumen 18 ofthe aspiration catheter 4, a second steady pressure curve 75 ismeasured. The duration 67 of the deviation 77 is the amount of transitof the particular significant pieces or portions 90 of thrombus 88. Theduration 67 can range quite a bit, but in some cases may be less than asecond or up to about 30 seconds. A single thrombus being aspirated maycause a single decrease in pressure (a blip) which is identified by themeasurement device 54, 64. Subsequently, this occurrence may becommunicated to the user by the communication device 58 a-c, 74. Whenagain additional pieces or portions 90 of thrombus 88 are aspirated intoand travel down the aspiration lumen 18 of the aspiration catheter 4,another deviation 73 of fluid pressure comprising a one or moredecreases and increases in pressure (increases and decreases in vacuumpressure) is measured. At the end of the curve 79, the vacuum source 6is shown filling completely with blood 96 and the pieces or portions 90of thrombus 88, and so an upward slope 95 is measured.

The measurement device 54, 64 is configured to compare the curve 79 withinformation stored in the memory module 56, 66 to identify when thepieces or portions 90 of thrombus 88 are actively being aspirated, as indeviation 77 and deviation 73, and when the pieces or portions ofthrombus 88 are not being actively, or substantially, aspirated, as insteady pressure curve 97, the steady pressure curve 75, and the steadypressure curve 71. In some embodiments, the measurement device 54, 64uses an algorithm to make the comparison. In some embodiments, a pre-setpressure differential ΔP₂ may be stored in the memory module 56, 66 as athreshold, whereby the measurement of a pressure difference 69 less thanthis threshold does not result in the measurement device 54, 64commanding the communication device 58 a-c, 74 to send a first type ofalert via an alert signal 60 a-c, 70. In some embodiments, when thepressure difference 69 is greater than (or greater than or equal to) thepre-set pressure differential ΔP₂, the measurement device 54, 64 thensends a signal to the communication device 58 a-c, 74, and thecommunication device 58 a-c, 74 generates an appropriate alert.Communication device 58 a, for example a particular color LED, may beilluminated, or an LED may flash in a particular pattern or number offlashes. In some embodiments, the communication device 58 a may comprisea light whose intensity increases proportionally with the pressure.Communication device 58 b may create a characteristic sound, or maygenerate an audio message in a number of languages. For example, theaudio message may state, “Thrombus being aspirated.” In someembodiments, communication device 58 b may comprise one or more noisesor beeps. In some embodiments, the communication device 58 b maycomprise a particular series of beeps corresponding to each differentcondition. For example, three short beeps may correspond to no thrombusbeing aspirated, while five long, loud beeps may correspond to a systemleak. In some embodiments, a plurality of different tones (pitches) maybe used to alert a user about different conditions. As an example, a lowpitch sound may be used for a first condition (e.g. no thrombus beingaspirated) and a second, higher pitch sound may be used for a secondcondition (e.g. a system leak). In some embodiments, a plurality ofdifferent tones may be used to alert a user about a first condition anda second plurality (e.g. in a different combination, or with additionaltones) may be used to alert a user about a second condition.Communication device 58 c may vibrate or heat in a characteristicpattern, for example, a certain number of repetitions or a certainfrequency between repetitions. When the user realizes that the thrombusis being aspirated, the user may choose to advance (or retract) theaspiration catheter 4, for example with fluoroscopic visualization,along the length of the thrombus 88, in an attempt to continue theaspiration of the thrombus 88. In some cases, the user may choose tostop the advancement or retraction of the aspiration catheter 4 at acertain amount of time after the alert is generated, in order to allowthe pieces or portions 90 of thrombus 88 to completely exit theaspiration lumen 18. When the measurement device 54, 64 identifies asubsequent steady pressure curve 75, 71 that follows a deviation 77, 73,the measurement device 54, 64 in some embodiments sends a signal thatcauses the communication device 58 a-c, 74 to generate a second type ofalert via an alert signal 60 a-c, 70. For example, in some embodiments,communication device 58 b may send an audio message that states,“Thrombus no longer being aspirated.” When the user realizes that thethrombus is no longer being aspirated, the user may advance or retractthe aspiration catheter, in an attempt to contact another portion of thethrombus 88 that can be aspirated. In some embodiments, the deviation 77may be positively identified as a true deviation indicating thrombusbeing actively aspirated, pressure difference 69 is between about 700pascal and about 1700 pascal. In some embodiments, the deviation 77 maybe positively identified as a true deviation indicating thrombus beingactively aspirated, pressure difference 69 is between about 1000 pascaland about 1300 pascal. In some embodiments, the deviation 77 may bepositively identified as a true deviation indicating thrombus beingactively aspirated, pressure difference 69 is about 1138 pascal. Thepressure difference 69 may be measured by determining a baselinepressure 63 and a peak pressure 61 and determining the absolute valuedifference. For example:Absolute value difference (AVD)=|(−89,631 pascal)−(−90,769 pascal)|=1138pascal

Or for example:Absolute value difference (AVD)=|(−43,710 pascal)−(−45,102 pascal)|=1281pascal

The pressure difference 81 (FIG. 5B) may also represent a deviation thatmay be identified in a similar manner, after which the communicationdevice 58 a-c, 74 generates an appropriate alert, such as, “Clogcondition.”

Because vacuum pressure is a negative pressure, the peak pressure 61, asshown in FIG. 5D, is actually a lower number than the baseline pressure63. In some embodiments, the measurement device 54, 64 may also beconfigured to make a comparison, for example by using an algorithm,between a stored differential time ti and a duration 65 of a single oneof the more or more decreases and increases in pressure in the deviation77. For example, in some embodiments, the deviation may be positivelyidentified as a true deviation indicating thrombus being activelyaspirated, if the duration is between about 0.001 seconds and about 0.50seconds. In some embodiments, the deviation may be positively identifiedas a true deviation indicating thrombus being actively aspirated, if theduration is between about 0.005 seconds and about 0.10 seconds. In someembodiments, the deviation may be positively identified as a truedeviation indicating thrombus being actively aspirated if the durationis between about 0.05 seconds and about 0.20 seconds. In someembodiments, the measurement device 54, 64 is configured to recognizedeviation 77 after two or more decreases and increases in pressure aremeasured. In some embodiments, the measurement device 54, 64 isconfigured to recognize deviation 77 after five or more decreases andincreases in pressure are measured. In some embodiments, the measurementdevice 54, 64 is configured to recognize deviation 77 after ten or moredecreases and increases in pressure are measured.

The baseline pressure 63 may in some embodiments be predetermined andmay be stored in the memory module 56, 66. In some embodiments, thebaseline pressure 63 may be stored in in the memory module 56, 66 duringthe manufacture of the aspiration monitoring system 48, 62, 78, but thebaseline pressure 63 may also be input by the user prior to or during aparticular procedure. In some embodiments, the baseline pressure 63 maybe determined or otherwise defined by the measurement device 54, 64, 76based on averaging of a particular number of samples of measuredpressure. The baseline pressure 63 may be constructed as a movingaverage, such as a running average or rolling average. Several types ofmoving average may be used, including a simple moving average, acumulative moving average, a weighted moving average, or an exponentialmoving average. In any of these cases, a threshold may be determined bythe measurement device 54, 64, 76 based on the determined baselinepressure 63 and a known pressure differential ΔP. In some case, apressure differential ΔP may even be calculated by the measurementdevice 54, 64, 76 based on the determined baseline pressure 63 and aknown threshold.

Insertion of the pressure transducer 12 in line in either the embodimentof FIG. 2A or the embodiment of FIG. 2B does not measurably changeperformance characteristics of the aspiration system 2, because thecavity 42 is relatively short and has a relatively large inner diameter,and thus is not a significant source of fluid flow resistance. In someembodiments, the inner diameter may be between about 2.2 mm (0.086inches) and about 3.2 mm (0.125 inches). In some embodiments, themeasurement device 54, 64, 76 need not include a microprocessor, aspre-defined set points (e.g. for certain thresholds) may be included infirmware, microcontroller, or other locations. In some embodiments,including but not limited to the embodiment of FIG. 2B, the pressuretransducer 12 may be an off-the-shelf blood pressure monitor system,which is modified or augmented with other components. In someembodiments an off-the-shelf blood pressure monitor system may be usedas the output of the aspiration monitoring system 48, 62, 78. In someembodiments, an aspiration catheter 4 may have a pressure transducer inthe distal end 16. This pressure transducer may be used as the pressuretransducer 12 of the aspiration monitoring system 48, 62, 78. In someembodiments, a pressure sensor may be located within a Tuohy-Borstvalve, and introducer sheath, a guiding catheter, or another componentof the system through which is in fluid communication with theaspiration lumen 18. In some embodiments, the pressure sensor may belocated anywhere within the aspiration lumen of the aspiration catheter.

In some embodiments, instead of an LED, the visual alert is provided bya communication device 58 a comprising a display which displays visualmessages of text in a particular language, for example, “Thrombusencountered,” “No thrombus encountered,” “Clog condition,” “Systemleak,” “Loss of vacuum,” “Thrombus being aspirated,” or “Thrombus nolonger being aspirated.” The visual messages may be combined with any ofthe other alert signals 60 a-c, 70 described herein. The aspirationmonitoring system 48, 62, 78 described herein give real time awarenessto users performing aspiration procedures, such as the removal ofthrombus via an aspiration system 2. One skilled in the art willrecognize that by knowing the real time condition of the aspirationsystem 2, the user is able to immediately make changes to the procedurein order to optimize results, increase safety for the patient and/ormedical personnel, reduce costs (e.g. number of vacuum sources 6required), and reduce procedure time (also a cost benefit). Because theuser is typically performing multiple tasks during an aspirationprocedure, the sensory aid provided by the aspiration monitoring system48, 62, 78 allows the user to focus on these tasks without having tocontinually attempt to monitor conditions which are often difficult tovisually monitor. The user may also modify and control the aspirationmonitoring system 48, 62, 78 via an input 59 (FIG. 2B), which maycomprise a data entry module, keyboard, or a series of buttons with adisplay. The input 59 may in some embodiments comprise an auditory inputwhich accepts voice commands. Alternatively, the user may inputinformation and control the aspiration monitoring system, 48, 62, 78remotely. Some of the alerts which the user may select or deselect inthe aspiration monitoring system 48, 62, 78 include, but are not limitedto: whether the aspiration system 2 is potentially blocked or clogged,or is flowing normally; whether thrombus has been contacted or not;whether a clog has occurred; whether the vacuum source 6 is adequate, orwhether it has been depleted and requires replacement; whether there isa leak in the aspiration system 2; whether setup or connection of thecomponents of the aspiration system 2 was done correctly or incorrectly;whether to advance the catheter distally; whether to retract thecatheter; whether to continue moving the catheter at the same speed;whether to increase or decrease the speed of catheter advancement;whether thrombus is actively being aspirated; and whether thrombus stopsbeing actively aspirated. As the user becomes familiar with theaspiration monitoring system 48, 62, 78, the user may even begin to makecertain responses to the system subconsciously. For example, a user mayautomatically pull back the catheter upon hearing a clot warning signal(e.g., three beeps), and may automatically begin advancing the catheterand/or start fluoroscopic visualization upon hearing a free blood flowsignal (e.g., two beeps). By being “at one” with the aspirationmonitoring system 48, 62, 78 and the catheter, the user optimizesreactions and actions. This may be helpful improving the skill of havingthe catheter take a small “bite” of thrombus, and following the “bite”with a “chaser” of some fast flowing blood, the clean/open the lumen.This would also help minimize the chance of clogging, and would in turnreduce maintenance or corrections of the system (removing the catheter,flushing the lumen outside of the patient, replacing the catheter). Theoverall experience for the user is improved, as the user receivesinstant gratification for good results, and is instantly notified oferrors or instances for concern.

In some embodiments, alternate power sources may be used, for example,standard AC power with or without an AC/DC convertor; direct connectionto existing equipment (e.g. vacuum pumps, etc.); solar power. Theaspiration monitoring system 48, 62, 78 may be packaged sterile or maybe resterilizable by techniques known by those skilled in the art. Insome embodiments, flow or volume gauges may be used in conjunction withor instead of the pressure gauge 12, in order to determine, for example,a clog, or a change in the amount of vacuum. In some embodiments, theinput 59, power module 72, measurement device 64, memory module 66, andcommunication device 68 (e.g., of FIG. 2B) may all be incorporated intoa single external device, which may in some cases be sold separately. Insome embodiments, the external device may also have other functions,such as providing aspiration and/or injection (negative pressure and/orpositive pressure) to a catheter. In other embodiments, the externaldevice may comprise some, but not all of the input 59, power module 72,measurement device 64, memory module 66, and communication device 68.For example, in some embodiments, a communication device 58 (FIG. 2A)may replace the external communication device 68, and may be carried onthe aspiration monitoring system 48, while the input 59, power module72, measurement device 64, memory module 66 (FIG. 2B) are incorporatedinto a single external device. A number of combinations are possible, asdescribed in more detail herein.

Though aspiration of thrombus has been described in detail, theaspiration monitoring system 48, 62, 78 has utility in any aspirationapplication wherein heterogeneous media is being aspirated. This mayinclude the aspiration of emboli (including not thrombotic emboli) fromducts, vessels, or cavities of the body, or even from solid orsemi-solid portions of the body, including, but not limited to, portionsof fat, breasts, and cancerous tissue.

In some embodiments, the aspiration system 2 is be provided to the useras a kit with all or several of the components described, while in otherembodiments, only the aspiration monitoring system 48 is provided.Though discussion herein includes embodiments for aspiration of thrombusand blood, the definition of the word “fluid” should be understoodthroughout to comprise liquids and gases.

In some embodiments, an additional or alternate sensor may be used tomonitor flow conditions for the notification of the user, including, butnot limited to: a Doppler sensor, an infrared sensor, or a laser flowdetection device. In some embodiments, an externally-attached Dopplersensor may be employed. In some embodiments, an infrared sensor or alaser flow detection device may be employed around the extension tubing10.

Additional embodiments allow real time communication of the particularvalue of fluid pressure (for example the level of vacuum) measured bythe sensor 50. For example, as the amount of vacuum increases, anaudible sound may increase in sound intensity or in sound pressure level(dB) proportionally. Or, as the amount of vacuum increases, the pitch(frequency) of an audible sound may made to rise, and as the amount ofvacuum decreases, the pitch may be made to fall (as does a siren). Bycontrolling either the amplitude of a signal or the frequency of asignal by making them proportional to the fluid pressure, the system cangive a user a real-time sense of whether the vacuum is increasing,decreasing, or staying the same, as well as whether the pressure isclose to zero or quite different from zero. When an audible sound isused as the signal, the user's eyes can remain focused on the procedure,whether by viewing a monitor of fluoroscopic images, the patient, or aseparate piece of equipment.

FIG. 6 illustrates a graph 800 of time (x-axis) and multiple variables(y-axis). A pressure curve 802 shows a vacuum being applied at apressure drop 808, and a maintenance of vacuum 810 a with a decrease invacuum 812 and an increase in vacuum 814. A removal of vacuum 816 isshown at the end of the pressure curve 802. In some cases, the decreasein vacuum 812 may be caused by a temporary or permanent leak ordetachment within the system or by filling of the vacuum source (e.g.,syringe). In FIG. 6 , the decrease in vacuum 812 is shown as temporary,as a subsequent maintenance of vacuum 810 b is illustrated. The increasein vacuum 814 may in some cases be caused by thrombus being suckedthrough the system and may occur for a short or long amount of time, andmay be steady or intermittent. Though the amount of vacuum applied inthe pressure curve 802 varies, in some embodiments, it may only bedesirable to show to a user only whether the vacuum is generally beingapplied or not being applied. The measurement device 54, 64, 76 may beconfigured to apply an algorithm to the signal from the vacuum sensor 50(pressure sensor) that calculates an inverse value, represented by thedashed curve 804. The measurement device 54, 64, 76 further may apply analgorithm that increases, amplifies or otherwise augments the signal forease of identification, for example within the human range of audibleidentification (hearing). For example, a modified signal curve 806 maybe created that has the following general mathematical relationship withthe signal from the vacuum sensor 50 represented by the pressure curve802.Sound Pressure Level (dB)=A+B×(1/fluid pressure)

-   -   where A is a first constant, and    -   B is a second constant

In one particular example, a modified signal curve 806 may be createdthat has the following mathematical relationship with the signal fromthe vacuum sensor 50 represented by the pressure curve 802.Sound Pressure Level (dB)=70+20×(1/fluid pressure (kPa))

-   -   where dB is units in decibels, and    -   kPa is units of kiloPascal

The modified signal curve 806 may be constructed of an algorithm suchthat the sound pressure level drops below the audible level of humanhearing at relatively small amounts of vacuum, thus giving the user an“on/off” awareness of the vacuum being applied.

FIG. 7 illustrates a graph 820 of time (x-axis) and multiple variables(y-axis). A pressure curve 822 shows a vacuum being applied at apressure drop 828, and a maintenance of vacuum 830 a with a decrease invacuum 832 and an increase in vacuum 834. A removal of vacuum 836 isshown at the end of the pressure curve 822. In some cases, the decreasein vacuum 832 may be caused by a temporary or permanent leak ordetachment within the system or by filling of the vacuum source (e.g.,syringe). In FIG. 7 , the decrease in vacuum 832 is shown as temporary,as a subsequent maintenance of vacuum 830 b is illustrated. The increasein vacuum 834 may in some cases be caused by thrombus being suckedthrough the system and may occur for a short or long amount of time, andmay be steady or intermittent. In some cases or configurations, it maybe desirable for the user to have a very specific real-time or close toreal-time characterization of the amount or level of vacuum (or pressurein general) being applied. The measurement device 54, 64, 76 may beconfigured to apply an algorithm to the signal from the vacuum sensor 50(pressure sensor) that calculates an absolute value, represented by thedashed curve 824. The measurement device 54, 64, 76 further may apply analgorithm that increases, amplifies or otherwise augments the signal forease of identification, for example within the human range of audibleidentification (hearing). For example, a modified signal curve 826 maybe created that has the following general mathematical relationship withthe signal from the vacuum sensor 50 represented by the pressure curve822.Sound Pressure Level (dB)=A+B×|(fluid pressure)|

-   -   where A is a first constant, and    -   B is a second constant

In one particular example, a modified signal curve 826 may be createdthat has the following mathematical relationship with the signal fromthe vacuum sensor 50 represented by the pressure curve 822.Sound Pressure Level (dB)=2×|(fluid pressure (kPa))|

-   -   where dB is units in decibels and,    -   kPa is units of kiloPascal

The modified signal curve 826 may be constructed of an algorithm suchthat the sound pressure level seems to the user to follow the amount ofvacuum being applied, thus becoming louder as the vacuum is increased.

FIG. 8 illustrates a graph 840 of time (x-axis) and multiple variables(y-axis).

A pressure curve 842 shows a vacuum being applied at a pressure drop848, and a maintenance of vacuum 850 a with a decrease in vacuum 852 andan increase in vacuum 854. A removal of vacuum 856 is shown at the endof the pressure curve 842. In some cases, the decrease in vacuum 852 maybe caused by a temporary or permanent leak or detachment within thesystem or by filling of the vacuum source (e.g., syringe). In FIG. 8 ,the decrease in vacuum 852 is shown as temporary, as a subsequentmaintenance of vacuum 850 b is illustrated. The increase in vacuum 854may in some cases be caused by thrombus being sucked through the systemand may occur for a short or long amount of time, and may be steady orintermittent. As mentioned, in some cases or configurations, it may bedesirable for the user to have a very specific real-time or close toreal-time characterization of the amount or level of vacuum (or pressurein general) being applied. The measurement device 54, 64, 76 may beconfigured to apply an algorithm to the signal from the vacuum sensor 50(pressure sensor) that calculates an absolute value, represented by thedashed curve 844. The measurement device 54, 64, 76 further may apply analgorithm that determines a frequency of an audible sound (or pitch),for example within the human range of audible identification (hearing),that varies within the human range of audible frequencies. For example,a modified signal curve 846 may be created that has the followinggeneral mathematical relationship with the signal from the vacuum sensor50 represented by the pressure curve 842.Sound Frequency (Hz)=A+B×|(pressure)|

-   -   where A is a first constant, and    -   B is a second constant

In one particular example, a modified signal curve 846 may be createdthat has the following mathematical relationship with the signal fromthe vacuum sensor 50 represented by the pressure curve 842.Sound Frequency (Hz)=50×|(fluid pressure (kPa))|

-   -   where Hz is Hertz (l/second), and    -   kPa is units of kiloPascal

The modified signal curve 846 may be constructed of an algorithm suchthat the sound frequency seems to the user to follow the amount ofvacuum being applied. In this embodiment, the pitch of the sound becomes“higher” when vacuum is increased (fluid pressure decreases), and“lower” when the vacuum is decreased. Alternatively, the opposite mayinstead by chosen, wherein the pitch of the sound becomes lower whenvacuum is increased.

FIG. 9 illustrates a graph 860 of time (x-axis) and multiple variables(y-axis). A pressure curve 862 shows a vacuum being applied at apressure drop 868, and a maintenance of vacuum 870 with a one or moredecreases and increases in pressure 872. These one or more decreases andincreases in pressure 872 (or increases and decreases in vacuum) mayrepresent, in some instances, clot being sucked through aspiration lumenof an aspiration catheter. In some cases, a single decrease in pressure873 (increase in vacuum) may occur. The single decrease in pressure 873may in some cases be extended in duration, as shown in FIG. 9 , as mayany one of the one or more decreases and increases in pressure 872. Insome cases or configurations, it may be desirable for the user to have avery specific real-time or close to real-time characterization of theinstances when these small perturbations are occurring, as they maycorrespond to the catheter finding and aspirating a portion of thrombus.The measurement device 54, 64, 76 be configured to apply an algorithmthat determines a frequency of an audible sound (or pitch), for examplewithin the human range of audible identification (hearing), that varieswithin the human range of audible frequencies. For example, a modifiedsignal curve 866 may be created that has the following generalmathematical relationship with the signal from the vacuum sensor 50represented by the pressure curve 862.Sound Frequency (Hz)=A+B×(fluid pressure)

-   -   where A is a first constant, and    -   B is a second constant

In one particular example, a modified signal curve 866 may be createdthat has the following mathematical relationship with the signal fromthe vacuum sensor 50 represented by the pressure curve 862.Sound Frequency (Hz)=40×(fluid pressure (kPa))

-   -   where Hz is Hertz (1/second), and    -   kPa is units of kiloPascal

It should be noted that in this equation, no absolute value is used, butrather the actual value of fluid pressure. Or in some cases, an absolute(or negative) value may be used.

The modified signal curve 866 may be constructed of an algorithm suchthat the sound maintains a steady pitch until the clot is being suckedthrough the catheter, at which time the pitch changes slightly, butdistinctly, away from a steady pitch. For example, in some embodiments,the pitch may change between about 20 Hz and about 2000 Hz to correspondto a pressure change of between about one kPa to about two kPa, orbetween about 40 Hz and about 80 Hz.

In any of the examples, the modification of signals may include any typeof signal conditioning or signal modification that may be performed,including, but not limited to filtering, amplification, or isolation.The modified signal curve 806, 826, 846, 866 is used to determine theoutput signal to be generated by the communication device 58, 68, 74. Asmentioned, if the output signal of the communication device 58, 68, 74is configured to be an audible sound, the sound pressure level may bevaried, or the sound frequency may be varied. In some embodiments, theoutput signal of the communication device 58, 68, 74 may have both itssound pressure level and sound frequency varied. In one embodiment, thesound frequency varies continuously in proportion to fluid pressure, butat one or more particular thresholds of fluid pressure, the soundpressure level may be caused to vary quite suddenly and strikingly. Thusthere is a two-part communication occurring, a continuous real-timestatus indicator, with an intermittent, alert indicator (failure,danger, etc.). In some cases, the continuous real-time status indicatormay represent a first continuous signal and the alert indicator mayrepresent a second alert signal. In other cases, the continuousreal-time status indicator and the alert indicator may be combined orintegrated into the same signal. In some embodiments, othercharacteristics of psychoacoustics may be varied using variable soundgeneration devices. In some embodiments, the spectral envelope may bevaried. In some embodiments, timbre may be changed to varies levelsbetween light and dark, warm and harsh, or different noise “colors”(pink, white, blue, black, etc.).

Though an audible output from the communication device 58, 68, 74 hasbeen described with the examples from FIGS. 6-9 , other communicationsignals may be used, including visual or tactile signals. Tactilesignals may also include vibration devices or heat generation devices,either of which could be varied (as described) in relation to themeasured fluid pressure. Either the amplitude of the frequency couldanalogously be varied in communication signals that include signalsother than the audible signals already described. For example, theintensity of a light can be varied, or the frequency (e.g., color) of alight can be varied. The amplitude of displacement of a vibration devicecan be varied (or other techniques that vary the vibration intensity) orthe frequency of the vibration can be varied.

In some cases, a pseudo-continuous analog may be used in place of atruly variable output. For example, instead of a single light whoseintensity is continuously varied, an array of multiple lights, forexample and array comprising multiple LEDs, may be used, with anincreased number of LEDs being lit when the level of vacuum isincreased, and a decreased number of LEDs being lit when the level ofvacuum is decreased. The same may be possible with an array comprisingmultiple vibrating elements, wherein more elements begin vibrating uponan increase or decrease, depending on the application, of fluidpressure.

In any of the embodiments described in relation to FIGS. 6-9 , theequations for sound pressure level or for sound frequency which dependon fluid pressure as a variable, may depend on actual measured fluidpressure, or an absolute value of actual measured fluid pressure, butmay also use measured fluid pressure in an alternative manner. Forexample, with a baseline pressure 63 either pre-set, pre-determined, ordetermined or calculated by any other method (averaging, etc.), thedifferential between the measured pressure and the baseline pressure 63may be used as the variable on which to base the particular dependency(e.g., proportionality).

Thus, a base mathematical relationship used with the proportionalitydescribed with respect to the embodiment of FIG. 6 may be representedas:Sound Pressure Level (dB)=A+B×(1/ΔP)

-   -   where A is a first constant,    -   B is a second constant, and    -   ΔP is a difference or differential between a baseline pressure        and a measured fluid pressure.

Likewise, a base mathematical relationship used with the proportionalitydescribed with respect to the embodiment of FIG. 7 may be representedas:Sound Pressure Level (dB)=A+B×|(ΔP)|

-   -   where A is a first constant,    -   B is a second constant, and    -   ΔP is a difference or differential between a baseline pressure        and a measured fluid pressure.

Likewise, a base mathematical relationship used with the proportionalitydescribed with respect to the embodiment of FIG. 8 may be representedas:Sound Frequency (Hz)=A+B×|(ΔP)|

-   -   where A is a first constant,    -   B is a second constant, and    -   ΔP is a difference or differential between a baseline pressure        and a measured fluid pressure.

Likewise, a base mathematical relationship used with the proportionalitydescribed with respect to the embodiment of FIG. 9 may be representedas:Sound Frequency (Hz)=A+B×(ΔP)

-   -   where A is a first constant,    -   B is a second constant, and    -   ΔP is a difference or differential between a baseline pressure        and a measured fluid pressure.

A pressure transducer 912 of an aspiration monitoring system 900 isillustrated in FIG. 10 , for coupling to an aspiration system includingan aspiration catheter 4. The pressure transducer 912 includes a housing40, a first port 44, a second port 46 and a cable 902 for carrying asignal. The cable 902 includes an interface 904, or plug, which isconfigured to connect to a port 906 of a console 908 of the aspirationmonitoring system 900. The housing 40 of the pressure transducer 912includes a cavity 42 extending between the first port 44 and the secondport 46. The console 908 is powered by a power module 972, which isconnected to the console 908, and may comprise a source of AC or DCpower. The console 908 may include a measurement device 964, a memorymodule 966 and a communication device 968, which may be coupled coupledto each other as described in the prior embodiments and configured suchthat the communication device 968 is capable of creating a signal 970,which may be an alert signal, a continuous signal, a combined signal, orother type of signal. The console 908 may also include wired or wirelessconnections to other interfaces or displays which may be found in healthcare sites, such as a monitor 931. In some embodiments, the monitor 931may be a monitor which also displays fluoroscopy or angiogram images, ora monitor which also displays electrocardiography or blood pressuregraphics or other information. The monitor 931 may have a portion thatmaintains the status of the aspiration. For example, it may read“Thrombus being aspirated” or “No thrombus detected.” The pressuretransducer 912 (housing 40, ports 44, 46, cable 902, interface 904) maybe sold sterile, and may be configured to output a signal that isreceived by the console 908, for example the measurement device 964 ofthe console 908. The pressure transducer 912 may have its own internalsource of power (e.g., the battery 52 in FIG. 2A), or may be powered byits connection to the console 908, or alternatively, by its connectionto the aspiration catheter 4, or even the extension tubing 10. In someembodiments, the console 908 may be configured to identify and/orrecognize the pressure transducer 912, for example, to recognize theparticular model of the pressure transducer 912. In some embodiments,the console 908 may be configured to measure a resistance between twoelectrical contacts in the pressure transducer 912 in order to identifythe type (e.g., model) of pressure transducer. In some embodiments, theconsole 908 may be configured to read an RFID chip on the pressuretransducer 912. The console 908 may also be configured to connect to twoor more different models of pressure transducer. The port 906, maycomprise at least one port, which may comprise two or more ports, eachport configured to allow connection of a different model of pressuretransducer.

An aspiration system 1000 in FIG. 11 includes an aspiration console 1001having a connector 1002, or hub, (e.g., male luer) for connecting to anaspiration catheter 4, for example, to a connector 22 (e.g., femaleluer) of the aspiration catheter 4. The aspiration console 1001 ispowered by a power module 972, which is connected to the aspirationconsole 1001, and may comprise a source of AC or DC power. Theaspiration console 1001 may include a canister 1006 for collecting theaspirated materials, and may include a vacuum pump 1004 for creating avacuum with which to create the aspiration. Tubing 1008 may be connectedbetween the canister 1006 and the connector 1002. In some embodiments,the canister 1006 is removable or replaceable. An aspiration monitoringsystem 900 includes a pressure sensor 1010 (e.g., a vacuum sensor) influid communication with the tubing 1008. The tubing 1008 may insteadcomprise a lumen formed inside fabricated parts. The aspirationmonitoring system 900 is shown in more detail in FIG. 12 , and mayinclude some or all of the features described in relation to FIG. 10 .The aspiration console 1001 may also include wired or wirelessconnections to other interfaces or displays which may be found in healthcare sites, such as a monitor 931. In some embodiments, the monitor 931may be a monitor which also displays fluoroscopy or angiogram images, ora monitor which also displays electrocardiography or blood pressuregraphics or other information. By combining all communication related tothe procedure on or at a single monitor or single monitor location,uninterrupted focus can be achieved by the user, who may be freelydedicated to the safe advancement and placement of the aspirationcatheter in proximity to the thrombus.

A system for forced (or assisted) aspiration 1100 in FIG. 13 includes anaspiration/injection console 1101 having a first connector 1016, or hub,(e.g., male luer) for connecting to an injection lumen 1020 of a forcedaspiration catheter 1013, and a second connector 1012, or hub (e.g.,male luer) for connecting to an aspiration lumen 1018 of the forcedaspiration catheter 1013. The first connector 1016 is configured toconnect to connector 1024 (e.g., female luer) of a y-connector 1022 andthe second connector 1012 is configured to connect to connector 1026 ofthe y-connector 1022 at a proximal end 14 of the forced aspirationcatheter 1013. The aspiration/injection console 1101 is powered by apower module 972, which is connected to the aspiration console 1101, andmay comprise a source of AC or DC power. The aspiration console 1101 mayinclude a canister 1106 for collecting the aspirated materials, and mayinclude a vacuum pump 1104 for creating a vacuum with which to createthe aspiration. Tubing 1108 may be connected between the canister 1106and the connector 1012. A positive pressure pump 1014 is coupled to afluid source 1032 (e.g., a saline bag) and is configured to injectinfusate out the connector 1016 at a high pressure. An aspirationmonitoring system 900 includes a pressure sensor 1110 (e.g., a vacuumsensor) in fluid communication with the tubing 1108. The tubing 1108 mayinstead comprise a lumen formed inside fabricated parts. The aspirationmonitoring system 900 is shown in more detail in FIG. 14 , and mayinclude some or all of the features described in relation to FIG. 10 .At a distal end 16 of the forced aspiration catheter 1013, the injectionlumen 1020 terminates in an orifice 1028, which is configured to createa jet 1030 formed from the high pressure infusate exiting the orifice1028. The jet 1030 enters the aspiration lumen 1018, thus creatingsuction at the distal end 16 of the forced aspiration catheter 1013,which forces materials (e.g., thrombus) into the aspiration lumen 1018,and into the canister 1106. The aspiration/injection console 1101 mayalso include wired or wireless connections to other interfaces ordisplays which may be found in health care sites, such as a monitor 931.In some embodiments, the monitor 931 may be a monitor which alsodisplays fluoroscopy or angiogram images, or a monitor which alsodisplays electrocardiography or blood pressure graphics or otherinformation.

In an alternative embodiment, the forced aspiration catheter 1013 of theaspiration catheter 4 may have an additional lumen or guide channel forplacement of an additional device or tool. In some embodiments, theguidewire lumen 26 may be used as this additional lumen, and may extendthe entire length or most of the length of the catheter, so that thelumen is accessible from the proximal end 14. The additional device ortool may comprise a laser fiber, a mechanical screw, a vibrating wire ora variety of other modalities for disrupting thrombus or other material.

In any of the embodiments presented, the system may be configured sothat most or all of the components are supplied together. For example, acatheter and an aspiration monitoring system that are permanentlyattached to each other. In some embodiments, the aspiration catheterand/or the aspiration monitoring system may include configurations thatpurposely make it difficult to reprocess (e.g., clean or resterilize)them, thus protecting from potential uses that are not recommended orwarranted, and which may risk patient infection and/or devicemalfunction. For example, the sensor or the portion adjacent the sensormay be purposely difficult to access or clean. Alternatively, one ormore batteries may be impossible to access or change.

In some embodiments, it may be desired to have other descriptivewarnings that can be tied to pressure measurement or pressuremeasurement combined with another measured attribute. For example, if asensor (accelerometer or temperature sensor) within the aspirationcatheter is used to detect catheter movement, a change in this sensormay be tied to the pressure sensor. In this manner, a catheter that isengaged with a thrombus at its tip and is moved (e.g., begins to bepulled out of the patient) may then cause a warning: “Warning, do notmove catheter; risk of thromboembolus.”

FIG. 15 is a diagrammatic figure depicting an assisted aspiration system510. The aspiration system 510 includes a remote hand piece 512 thatcontains a fluid pump 526 and an operator control interface 506. In onecontemplated embodiment, the system 510 is a single use disposable unit.The aspiration system 510 may also include extension tubing 514, whichcontains a fluid irrigation lumen 502 and an aspiration lumen 504, andwhich allows independent manipulation of a catheter 516 withoutrequiring repositioning of the hand piece 512 during a procedureperformed with the aspiration system 510. Extension tubing 514 may alsoact as a pressure accumulator. High pressure fluid flow from the pump526, which may comprise a displacement pump, pulses with each stroke ofthe pump 526 creating a sinusoidal pressure map with distinct variationsbetween the peaks and valleys of each sine wave. Extension tubing 514may be matched to the pump 526 to expand and contract in unison witheach pump pulse to reduce the variation in pressure caused by the pumppulses to produce a smooth or smoother fluid flow at tip of catheter516. Any tubing having suitable compliance characteristics may be used.The extension tubing 514 may be permanently attached to the pump 526 orit may be attached to the pump 526 by a connector 544. The connector 544is configured to ensure that the extension tubing 514 cannot be attachedto the pump 526 incorrectly.

An interface connector 518 joins the extension tubing 514 and thecatheter 516 together. In one contemplated embodiment, the interfaceconnector 518 may contain a filter assembly 508 between high pressurefluid injection lumen 502 of the extension tubing 514 and a highpressure injection lumen 536 of the catheter 516 (FIG. 17 ). Thecatheter 516 and the extension tubing 514 may be permanently joined bythe interface connector 518. Alternatively, the interface connector 518may contain a standardized connection so that a selected catheter 516may be attached to the extension tubing 514. In some embodiments, thefilter assembly 508 may be removably coupled to the extension tubing 514by a quick disconnect connection. A pressure transducer of an embodimentof the aspiration monitoring system presented herein may be located at apoint along the aspiration lumen 504 or any extension of the aspirationlumen 504.

Attached to the hand piece 512 are a fluid source 520 and a vacuumsource 522. A standard hospital saline bag may be used as fluid source520; such bags are readily available to the physician and provide thenecessary volume to perform the procedure. Vacuum bottles may providethe vacuum source 522 or the vacuum source 522 may be provided by asyringe, a vacuum pump or other suitable vacuum source. The filterassembly 508 serves to filter particulate from the fluid source 520 toavoid clogging of the high pressure injection lumen 536 and an orifice542 (FIG. 17 ). As described herein, distal sections of the highpressure injection lumen 536 may be configured with small innerdiameters, and to the filter assembly 508 serves to protect theircontinuing function. By incorporating one of a variety of catheters 516into the assisted aspiration system 510, for example with varying lumenconfigurations (inner diameter, length, etc.), a variety of aspirationqualities (aspiration rate, jet velocity, jet pressure) may be appliedin one or more patients. These aspiration qualities can be furtherachieved by adjustment of the pump 526, to modify pump characteristics(flow rate, pump pressure). In some embodiments, the catheter 516 may beused manually, for example, without the pump 526, and controlled by handinjection. The manual use of the catheter 516 may be appropriate forcertain patient conditions, and may serve to reduce the cost of theprocedure.

In one contemplated embodiment, the catheter 516 has a variablestiffness ranging from stiffer at the proximal end to more flexible atthe distal end. The variation in the stiffness of the catheter 516 maybe achieved with a single tube with no radial bonds between two adjacenttubing pieces. For example, the shaft of the catheter 516 may be madefrom a single length of metal tube that has a spiral cut down the lengthof the tube to provide shaft flexibility. Variable stiffness may becreated by varying the pitch of the spiral cut through different lengthsof the metal tube. For example, the pitch of the spiral cut may begreater (where the turns of the spiral cut are closer together) at thedistal end of the device to provide greater flexibility. Conversely, thepitch of the spiral cut at the proximal end may be lower (where theturns of the spiral cut are further apart) to provide increasedstiffness. A single jacket covers the length of the metal tube toprovide for a vacuum tight catheter shaft. Other features of catheter516 are described with reference to FIG. 17 , below.

FIG. 16 is a diagrammatic view showing more detail of the hand piece 512and the proximal portion of assisted catheter aspiration system 510. Thehand piece 512 includes a control box 524 where the power and controlsystems are disposed. The pump 526 may be a motor driven displacementpump that has a constant output. This pump displacement to cathetervolume, along with the location of the orifice 542 (exit) of thecatheter high pressure lumen 536 within the aspiration lumen 538 (FIG.17 ), ensures that no energy is transferred to the patient from thesaline pump as all pressurized fluid is evacuated by the aspirationlumen. A prime button 528 is mechanically connected to a prime valve530. When preparing the device for use, it is advantageous to evacuateall air from the pressurized fluid system to reduce the possibility ofair embolization. By depressing the prime button 528, the user connectsthe fluid source 520 to the vacuum source 522 via the pump 526. Thisforcefully pulls fluid (for example 0.9% NaCl solution, or “saline”, no“normal saline”, or heparinized saline) through the entire pump system,removing all air and positively priming the system for safe operation. Apressure/vacuum valve 532 is used to turn the vacuum on and offsynchronously with the fluid pressure system. One contemplated valve 532is a ported one way valve. Such a valve is advantageous with respect tomanual or electronic valve systems because it acts as a tamper proofsafety feature by mechanically and automatically combining theoperations of the two primary systems. By having pressure/vacuum valve532, the possibility of turning the vacuum on without activating thefluid system is eliminated.

The operator control interface 506 is powered by a power system 548(such as a battery or an electrical line), and may comprise anelectronic control board 550, which may be operated by a user by use ofone or more switches 552 and one or more indicator lamps 554. Thecontrol board 550 also monitors and controls several device safetyfunctions, which include over pressure and air bubble detection andvacuum charge. A pressure sensor 564 monitors pressure, and senses thepresence of air bubbles. Alternatively, an optical device 566 may beused to sense air bubbles. In one contemplated embodiment, the pumppressure is proportional to the electric current needed to produce thatpressure. Consequently, if the electric current required by pump 526exceeds a preset limit, the control board will disable the pump bycutting power to it. Air bubble detection may also be monitored bymonitoring the electrical current required to drive the pump at anyparticular moment. In order for a displacement pump 526 to reach highfluid pressures, there should be little or no air (which is highlycompressible) present in the pump 526 or connecting system (includingthe catheter 516 and the extension tubing 514). The fluid volume issmall enough that any air in the system will result in no pressure beinggenerated at the pump head. The control board monitors the pump currentfor any abrupt downward change that may indicate that air has enteredthe system. If the rate of drop is faster than a preset limit, thecontrol board will disable the pump by cutting power to it until theproblem is corrected. Likewise, a block in the high pressure lumen 536,which may be due to the entry of organized or fibrous thrombus, or asolid embolus, may be detected by monitoring the electrical currentrunning the pump 526. In normal use, the current fluxuations of the pump526 are relatively high. For example, the pump may be configured so thatthere is a variation of 200 milliAmps or greater in the current duringnormal operation, so that when current fluxuations drop below 200milliAmps, air is identified, and the system shuts down. Alternatively,current fluxuations in the range of, for example, 50 milliAmps to 75milliAmps may be used to identify that air is in the system.Additionally, an increase in the current or current fluxuations mayindicate the presence of clot or thrombus within the high pressure lumen536. For example, a current of greater than 600 milliAmps may indicatethat thrombus it partially or completely blocking the high pressurelumen 536, or even the aspiration lumen 538.

A vacuum line 556, connected to the vacuum source 522, may be connectedto a negative pressure sensor 558. If the vacuum of the vacuum source522 is low or if a leak is detected in the vacuum line 556, the controlboard 550 disables the pump 526 until the problem is corrected. Thenegative pressure sensor 558 may also be part of a safety circuit 560that will not allow the pump 526 to run if a vacuum is not present.Thereby a comprehensive safety system 562, including the safety circuit560, the pressure sensor 564 and/or the optical device 566, and thenegative pressure sensor 558, requires both pump pressure and vacuumpressure for the system to run. If a problem exists (for example, ifthere is either a unacceptably low pump pressure or an absence ofsignificant vacuum), the control board 550 will not allow the user tooperate the aspiration system 510 until all problems are corrected. Thiswill keep air from being injected into a patient, and will assure thatthe aspiration system 510 is not operated at incorrect parameters.

FIG. 17 is a diagrammatic view of the distal end portion 568 of theassisted catheter aspiration system 510, showing more details of thecatheter 516. The catheter 516 is a single-operator exchange catheterand includes a short guidewire lumen 534 attached to the distal end ofthe device. The guidewire lumen 534 can be between about 1 and about 30cm in length, or between about 5 and about 25 cm in length, or betweenabout 5 and about 20 cm in length, or approximately 13.5 cm in length.An aspiration lumen 538 includes a distal opening 540 which allows avacuum (for example, from vacuum source 522) to draw thrombotic materialinto the aspiration lumen 538. A high pressure lumen 536 includes adistal orifice 542 that is set proximally of distal opening 540 by a setamount. For example, distal orifice 42 can be set proximally of distalopening 540 by about 0.0508 cm (0.020 inches), or by 0.0508 cm±0.00762cm (0.020 inches±0.003 inches) or by another desired amount. The orifice542 is configured to spray across the aspiration lumen to macerateand/or dilute the thrombotic material for transport to vacuum source522, for example, by lowering the effective viscosity of the thromboticmaterial. The axial placement of the fluid orifice 542 is such that thespray pattern interaction with the opposing lumen wall produces a spraymist and not a swirl pattern that could force embolic material out fromthe distal opening 540. The system may be configured so that theirrigation fluid leaves the pump at a pressure of between about3,447,378 pascal (500 psi) and about 10,342,135 pascal (1500 psi). Insome embodiments, after a pressure head loss along the high pressurelumen 536, the irrigation fluid leaves orifice 542 at between about4,136,854 pascal (600 psi) and about 8,273,708 pascal (1200 psi), orbetween about 4,481,592 pascal (650 psi) and about 5,860,543 pascal (850psi). In some cases, it may be possible (and even desired) to use theassisted catheter aspiration system 510 without operating the pump 526,and thus use the catheter 516 while providing, for example, a handsaline injection via a syringe. Or, in some cases, the assisted catheteraspiration system 510 may be used without the pump 526 attached, withthe saline injections done by hand using a syringe through the highpressure lumen 536. If a clog occurs, the syringe may be removed and thepump 526 attached and initiated, for example, for the purpose ofunclogging the high pressure lumen 536.

When normal blood flow is achieved after unblocking occlusions orblockages from atherosclerotic lesions and/or thrombosis, there issometimes a risk of reperfusion injury. This may be particularlysignificant following thrombectomy of vessels feeding the brain fortreatment of thromboembolic stroke, or following thrombectomy ofcoronary vessels feeding the myocardium. In the case of therevascularization of myocardium following a coronary intervention (e.g.thrombectomy). Reperfusion injury and microvascular dysfunction may bemechanisms that limit significant or full recovery of revascularizedmyocardium. The sudden reperfusion of a section of myocardium that hadpreviously been underperfused may trigger a range of physiologicalprocesses that stun or damage the myocardium. Distal coronary emboli,such as small portions of thrombus, platelets and atheroma, may alsoplay a part. Controlled preconditioning of the myocardium at risk hasbeen proposed to limit the effect of reperfusion injury andmicrovascular dysfunction. The embodiments of the thrombectomy systems100, 300 presented herein may be combined with additional features aimedat allowing flow control, in order to limit the potential dangers due toreperfusion following thrombectomy. Other contemplated embodiments of anassisted aspiration system 510 which may be utilized are disclosed inU.S. Patent Application Publication No. 2010/0094201 to Mallaby(“Mallaby”) published Apr. 15, 2010, which is incorporated herein byreference in its entirety for all purposes. Other contemplatedaspiration catheters are disclosed in U.S. Patent ApplicationPublication No. 2008/0255596 to Jenson et al. (“Jenson”) published Oct.16, 2008, which is incorporated herein by reference in its entirety forall purposes.

FIG. 18 illustrates a multi-purpose system 1200 comprising amulti-purpose catheter 1202 having an infusion/injection port 1204 andan aspiration port 1206. The infusion/injection port 1204 and theaspiration port 1206 may each comprise luer connectors, such as femaleluer lock connectors. A tubing set 1208 and a pressure sensor 1210 areconnected in line with a vacuum source 1212. A cable 1214 carriessignals from the pressure sensor 1210 to an aspiration monitoring system1216 (FIG. 19 ), and connects to the aspiration monitoring system 1216via an interface 1218, or plug, which is configured to connect to a port1220 of a console 1222 of the aspiration monitoring system 1216.Apparatus and methods described herein may be used to monitor aspirationusing the aspiration monitoring system 1216. In one manner of use, asyringe 1224 (FIG. 18 ) may be used to manually inject through theinjection port 1204 and injection lumen 1225 (e.g., high pressure lumen)of the multi-purpose catheter 1202. The syringe 1224 may have aninjectable volume of about 5 ml or less, or in some embodiments about 1ml or less. The injection lumen 1225 in some embodiments may beconfigured for injection of saline at a relatively high pressure, or ateither high or low pressures. If the valve 1226 (e.g., stopcock) isclosed, blocking the vacuum source 1212 from applying a vacuum to theaspiration lumen 1227 via the aspiration port 1206, then injectionthrough the injection lumen 1225 causes injectate to be delivered to asite in the blood vessel near the distal exit of the injection lumen1225 (at the distal end of the multi-purpose catheter 1202). Or, if thevacuum source 1212 is removed from, or simply not coupled to, theaspiration lumen 1227, then injection through the injection lumen 1225may also cause injectate to be delivered to a site in the blood vesselnear the distal exit of the injection lumen 1225. Either of thesetechniques may be utilized to apply a medicant to a blood vessel wall,or to an atherosclerotic plaque, or to a thrombus. In some cases, a clotbusting drug (tissue plasminogen activator-tPA, thrombokinase,urokinase, thrombin, plasmin) is infused into a clot or thrombus,allowing it to act over a period of time. One purpose may be to softenthe thrombus over time. Lytics, glycoprotein inhibitors (GPIs),vasodilators, and other drugs may be used to dilate the blood vessel, ortreat disease in the area. The controlled, precision, local deliveryallows an efficient use of the drug, with the desired amount deliveredto the tissue to be treated with minimal runoff or waste. As many ofthese drugs are quite expensive, this efficiency reduces proceduralcosts. Because of the precision diameter of the injection lumen 1225,and its known length, the injection lumen 1225 contains a known volume,or dead space. This additionally allows a known, controlled, precisioninjection of medicant. A representative injection lumen 1225 may have alength of 150 cm and have an inner diameter of 0.038 cm (0.015 inches),and thus a total volume of only 0.17 ml. The injection lumen 1225 volumemay be varied, by controlling the diameter of the inner diameter of theinjection lumen 1225 and/or the length of the injection lumen 1225. Forexample, the injection lumen 1225 volume may be between about 0.08 mland about 0.26 ml, or between about 0.14 ml and about 0.20 ml. Byinjecting through the injection lumen 1225 with a small bore syringe(e.g., 1 ml) or with a precision pump, an accurate measurement of themedicant delivered can be made. If, however, the valve 1226, orstopcock, is opened, connecting the vacuum source 1212 to the aspirationport 1206 and applying a vacuum on the aspiration lumen 1227, a forcedaspiration is commenced, as described herein. As described, theinjection lumen 1225 may serve either a closed system (aspiration) or anopen system (injection of infusate). At the beginning of a procedure, itis not always known what different actions will be required, thus theuse of the multi-purpose catheter 1202 and multi-purpose system 1200 mayeliminate the need to use multiple catheters (e.g., both a microcatheterand a single function aspiration catheter).

FIGS. 20-24 illustrate a multi-purpose system 1240 comprising amulti-purpose catheter 1242 having an infusion/injection port 1244 andan aspiration port 1246. Cooled saline may be injected from a saline bag1248 (FIG. 23 ) through a tubing set 1250, attached to the saline bag1248 via a spike 1252. A pump 1254 (FIG. 24 ), which may include adisplacement pump, such as a piston pump, includes an interface 1256 forattaching a cassette 1258 (FIG. 20 ). In some embodiments, the pump 1254has moving portions that connect to a moving piston 1255 in the cassette1258 to inject controlled amounts of fluid. As described in relation tothe multi-purpose system 1200 of FIG. 18 , the injection may serveeither a closed system (aspiration) or an open system (injection ofinfusate), depending on whether a valve 1260 which couples a vacuumsource 1262 to the aspiration port 1246 via extension tubing 1264 isopen or closed, or simply whether the vacuum source 1262 is attached ornot attached. A pressure sensor 1266 communicates with the interior ofthe extension tubing 1264, but may communicate with the interior ofother parts of the flow path. A cable 1268 carries signals from thepressure sensor 1266 to an aspiration monitoring system 1270 (FIG. 22 ),and connects to the aspiration monitoring system 1270 via an interface1272, or plug, which is configured to connect to a port 1274 of aconsole 1276 of the aspiration monitoring system 1270. The utility ofthe multi-purpose systems 1200, 1240 in multiple modes is facilitated bythe sterile fluid path combined with precision volume control (either bysmall syringe 1224, or by the precision pump 1254). In addition, theaspiration monitoring system 1216, 1270 allows real-time feedback to theuser, further facilitating controlled delivery and/or aspiration.

The multipurpose system 1200, 1240 optimizes interventional procedures,such as percutaneous coronary interventions (PCIs), for simplicity, caseflow, and cost. Infusing drugs intracoronary prepares clot foraspiration by placing highly concentrated pharmaco agents directly atthe lesion site, at a location which can be more distal (e.g., moresuperselective) than that which is typically accessible by the tip of aguiding catheter. This can minimize the volume of drug/medicant/agentused. By limiting the amount of certain medicants, systemiccomplications (bleeding, etc.) can be minimized or eliminated. Thedirect application of the medicant, for example at the thrombus itself,allows it to soften or disaggregate the thrombus. The maceration of thethrombus, for example by a saline jet 1278 (FIG. 21 ) injected throughthe injection lumen 1257 of the multi-purpose catheter 1242, keeps thecatheter aspiration lumen 1259 patent at all times without interruption,and allows standardized catheter advancement technique, for example,moving the catheter slowly from a proximal location to a distal locationin the vessel (in relation to the thrombus). The maceration also dilutesthe proximally flowing aspirate for optimal suction function. In certainsituation, aspiration may be performed until the normal blood flow isrestored (at least to a significant level), and then the vacuum source1262 may be closed off via the valve 1260 and cooled injectate may beinfused into the blood vessel. The resultant selective cooling of thisarea serves to reduce reperfusion injury by potentially slowing ischemiccell metabolism. The injection of cooled infusate may be used any timepost-aspiration, pre-stenting, without having to remove an aspirationdevice, advance a new injection device. Because the multi-purposecatheter 1202, 1242 is already in place, this critical operation may bestarted immediately. By having these functionalities all on onecatheter, there is also a cost saving to the user.

In aspiration mode, the aspiration monitoring system 1216, 1270 is ableto monitor proper function of the aspiration circuit at all times. Theuser knows when warnings are communicated or when the system (e.g.,motor) shuts down, that a key event has occurred, an event that needsattending. This knowledge helps the user avoid plunging the catheterdistally, potentially causing distal embolism. In infusion/infusatecooling mode, the pump 1254 pumps at a predetermined constant volume orspeed to deliver constant temperature cooling infusate. Core temperaturefeedback (e.g., via rectal, esophageal, ear or other temperature probes)may be used to indicate to the system that further cooling must stop.For example, a core body temperature below 35° C. or below 34° C. Thefeedback of a temperature below the threshold may be used to shut downthe pump and/or to send a warning. The infusate path, which is precisionand direct to the catheter tip and/or ischemic area, results inconcentrated cooling, causing the least systemic hypothermic potential.By bypassing the aspiration lumen (e.g., with the valve 1260 closed),unintentional embolic debris is less likely to be infused back into theblood vessel, and less likely to thus be sent downstream to criticalareas. This eliminates the need to exchange devices after flow has beenrestored.

In some cases, in infusion mode, infusate is injected into the fluidinjection lumen 1225, 1257 with a relatively low pressure. In somecases, maceration is performed at a relatively high pressure. In somecases, the multi-purpose system 1240 may be used without the pump 1254attached, with the saline injections done by hand using a syringeattached to the infusion/injection port 1244. If a clog occurs, thesyringe may be removed and the pump 1254 attached and initiated, forexample, for the purpose of unclogging the injection lumen 1257. In anexemplary procedure, a user places a catheter similar to themulti-purpose catheter 1202 of FIG. 18 or multi-purpose catheter 1242 ofFIGS. 20-21 in the vasculature. Initially, the user may choose to haveneither a pump 1254, nor a syringe 1224 (FIG. 18 ) attached to themulti-purpose catheter 1202, 1242. The user may then commence aspirationthrough the aspiration lumen 1227, 1259 via a vacuum source 1212, 1262,thus utilizing the multi-purpose catheter 1202, 1242 as a simple (vacuumonly) aspiration catheter. If at any time, the user determines thatadditional positive pressure injection of saline and/or medicant isneeded, for example, to overcome clogging, overcome slow aspiration, orto increase maceration or dilution of the thrombus, the user can attachthe pump 1254 or the syringe 1224 to the infusion/injection port 1204,1244 and begin injecting the saline and/or medicant.

In one embodiment, an aspiration system includes an elongate catheterhaving a proximal end and a distal end, the catheter including anaspiration lumen having a proximal end and a distal end and a highpressure injection lumen having a proximal end and a distal end andextending from a proximal end of the catheter to a location adjacent adistal end of the aspiration lumen, and at least one orifice at or nearthe distal end of the high pressure injection lumen and configured toallow high pressure liquid injected through the high pressure injectionlumen to be released into the aspiration lumen, wherein the proximal endof the high pressure injection lumen is configured to be repeatablycoupled to and uncoupled from one or more injection modules. In someembodiments, the one or more injection modules include a first injectionmodule and a second injection module. In some embodiments, the firstinjection module comprises a pump and the second injection modulecomprises a syringe. In some embodiments, the second injection modulecomprises a syringe having a volume of about 5 ml or less. In someembodiments, the second injection module comprises a syringe having avolume of about 1 ml or less. In some embodiments, the second injectionmodule comprises a syringe containing a drug.

FIGS. 25 through 33 illustrate several different embodiments of deviceshaving a pressure sensor 1300, which is configured to function as acomponent in an aspiration monitoring system sharing some or all of thefunctionality of any one of the aspiration monitoring systems 48, 62,78, 900, 1216, 1270 presented herein. FIG. 25 illustrates an aspirationcatheter 1302 having a distal end 1304 and a proximal end 1306, theproximal end 1306 comprising a female luer connector 1308. The pressuresensor 1300 is in fluid communication with (e.g., fluidly coupled to) alumen of the aspiration catheter 1302. FIG. 26 illustrates a tubing set1310 having a male luer 1312 and a female luer 1314, extension tubing1316, and a stopcock 1318. The pressure sensor 1300 is in fluidcommunication with a lumen of the extension tubing 1316. FIG. 27illustrates a stopcock 1320 having a male luer 1322, a female luer 1324,and a valve 1326, the valve 1326 located proximally of the pressuresensor 1300. The pressure sensor 1300 is in fluid communication with aninternal cavity of the stopcock 1320. FIG. 28 illustrates a stopcock1328 having a male luer 1330, a female luer 1332, and a valve 1334, thevalve 1334 located distally of the pressure sensor 1300. The pressuresensor 1300 is in fluid communication with an internal cavity of thestopcock 1328. FIG. 29 illustrates a syringe 1336 having a male luer1342, a barrel 1338, and a plunger 1340. The syringe 1336 may include alocking feature 1344, which allows the plunger 1340 to be locked inrelation to the barrel 1338, such as a VacLok® syringe. The pressuresensor 1300 is located distally of the barrel 1338 and is in fluidcommunication with an internal cavity of the barrel 1338.

FIG. 30 illustrates a syringe 1346 having a male luer 1352 (i.e., luerconnector, luer lock), a barrel 1348, and a plunger 1350. The syringe1346 may include a locking feature 1344. The pressure sensor 1300 is influid communication with an internal cavity of the barrel 1348, and maybe directly connected to either the barrel 1348 or the male luer 1352,or a hollow transition 1351 between them. FIG. 31 illustrates anaspiration system 1354 comprising a syringe 1356 having a male luer1357, a barrel 1358 and a plunger 1360. The syringe 1356 may include alocking feature 1344. The aspiration system 1354 also comprises aconnector assembly 1361 comprising a male luer 1362, a valve 1364, and afemale luer 1365 (connected under the male luer 1357 in FIG. 31 ). Thepressure sensor 1300 is in fluid communication with an internal lumen orcavity between the barrel 1358 of the syringe 1356 and the male luer1362 of the connector assembly 1361. FIG. 32 illustrates an aspirationsystem 1366 comprising a syringe 1368 having a male luer 1369, a barrel1370 and a plunger 1372. The syringe 1368 may include a locking feature1344. The aspiration system 1366 also comprises a connector assembly1373 comprising a male luer 1374, a valve 1376, and a female luer 1377(connected under the male luer 1369 in FIG. 32 ). The pressure sensor1300 is in fluid communication with an internal lumen or cavity betweenthe barrel 1370 of the syringe 1368 and the male luer 1374 of theconnector assembly 1373. FIG. 33 illustrates an aspiration system 1378comprising a syringe 1380 having a male luer 1382, a barrel 1384 and aplunger 1386. The syringe 1380 may include a locking feature 1344. Theaspiration system 1378 further comprises a tubing set 1388 having a maleluer 1390 and a female luer 1392. A valve 1394 is located eitherproximal or distal to the pressure sensor 1300. Extension tubing 1396may be utilized to connect one or more of the components of the tubingset 1388, but in some cases, the components may be connected directly.The pressure sensor 1300 is in fluid communication with an internallumen of the tubing set 1388. The stopcock or valve in any of theseembodiments may be a one-way stopcock or a three-way stopcock or aone-way valve or a three-way valve. Other embodiments may exist whichcombine one or more elements of each of the embodiments presentedherein. These embodiments are also included within the scope of thisdisclosure. In any of the embodiments in which a male luer is used, itmay be replaced with a female luer or another liquid-tight connector. Inany of the embodiments in which a female luer is used, it may bereplaced with a male luer or another liquid-tight connector. As such,either of the connector assemblies 1361, 1373 may be connected inreverse manner to the syringes 1356, 1368, i.e., wherein the distal endbecomes the proximal end and is thus connected to the syringe 1356,1368, and wherein the proximal end becomes the distal end.

FIG. 34 illustrates a thrombectomy system 300 which incorporates thehigh pressure injection of a liquid, for example sterile salinesolution, in order to macerate and aspirate thrombus 104. A guidingcatheter 108 has an inner lumen 110 extending between a proximal end 144and a distal end 120. A y-connector 148, coupled to the proximal end 144of the guiding catheter 108, includes a proximal seal 150 and a sideport152 and is configured to couple the inner lumen 110 of the guidingcatheter 108 to a vacuum source 146, as described in relation to theprior embodiments. A thrombectomy catheter 306 comprises a distal tube314 having a distal end 316 and a proximal end 318, the proximal end 318incorporating one or more sealing members 324 for sealing off an annulus342 between the guiding catheter 108 and the distal tube 314, asdescribed in relation to the prior embodiments. The distal tube 314 hasan aspiration lumen 330. A support/supply tube 368, having a lumen 370,is coupled to the distal tube 314. The support/supply tube 368 serves asa support member for pushing and pulling the thrombectomy catheter 306,but is also a conduit (via the lumen 370) for high pressure saline,which is injected from the proximal end 372 to the distal end 374. Thesaline is supplied from a saline source 376 (e.g. saline bag, bottle)and pressurized by a pump 378, through a supply tube 380 and through aluer connector 382 which is connected to a luer hub 384 coupled to thesupport/supply tube 368. In some embodiments, the support/supply tube368 comprises a hypo tube. In some embodiments, the support/supply tube368 comprises stainless steel or nitinol. The distal end 316 of thedistal tube 314 may include a skive 358, which aids in the trackabilityof the distal tube 314 through vasculature of a patient. In someembodiments, the inner diameter of the aspiration lumen 330 of thedistal tube 314 may be approximately one French size smaller than theinner diameter of the inner lumen 110 of the guiding catheter 108.

FIG. 35 illustrates the proximal end of a guiding catheter 108 used withaspiration catheters, such as the thrombectomy catheter 306 of FIG. 34 .A hemostasis valve 389 of y-connector 390 seals over both thesupport/supply tube 391 and the guidewire 28. The hemostasis valve 389(e.g., Touhy-Borst, longitudinally spring-loaded seal, etc.) must beadjusted to allow catheter and/or guidewire 28 movement (translation,rotation), but must keep air from being pulled into the lumens duringaspiration. Because of the continual adjustment often required to thehemostasis valve 389, for example, to aid movement of the catheterand/or guidewire, the hemostasis valve 389 may create significantvariability in the amount of air that may leak. A leak (e.g., atlocation 393) may be fast, and may be unknown to the user. A pressuresensor 394 used in conjunction with any of the aspiration monitoringsystems described herein allows the user to know immediately if the sealof the hemostasis valve 389 of the y-connector 390 is not correctlysealed. Additionally, any leaks between the distal luer 388 of they-connector 390 and the luer hub 386 of the guiding catheter 108 can bedetected by the aspiration monitoring system. Furthermore, any leaksbetween a luer 392 of the pressure sensor 394 and a sideport 395 of they-connector 390 or between a luer connector 396 of the extension tube387 and a luer fitting 397 of the pressure sensor 394 can be detected bythe aspiration monitoring system. The aspiration monitoring system maybe configured to be integral or attachable to any component of theaspiration circuit (e.g., aspiration catheter, syringe/vacuum source),or may be connected in series (at any point) between these components.In some embodiment, the aspiration monitoring system may comprise a flowor pressure sensor or detector that is in series or in parallel with thecomponents, or is configured to be placed in series or in parallel withthe components. In any of these configurations, a number of differentleak locations may be assessed by the aspiration monitoring system ofthe embodiments disclosed herein. The aspiration monitoring system maybe configured to detect: changes, relative changes, absolute changes,thresholds, absolute values, the presence of or the lack of pressureand/or flow. The aspiration monitoring system may be configured todetermine the operation status of a system including a catheter havingan aspiration lumen. In some cases, the aspiration monitoring system maybe configured to provide information about the operation of the systemthat is not discernable from typical clues such as angiography, sound,feel, or other visual, auditory, tactile or other feedback from thesystem itself.

FIG. 36 illustrates a syringe 10″ having a barrel 20″ that is configuredto rotate as the plunger 86″ of the syringe 10″ is drawn from the barrel20″. In some embodiments, the barrel 20″ and the corresponding plunger86″ may include cooperating rotation elements that cause the barrel 20″to rotate as the plunger 86″ is moved axially along (i.e., forced intoor withdrawn from) a receptacle 24″ of the barrel 20″.

In one specific embodiment, an interior surface 23″ of the barrel 20″carries one or more threads 27″ (two threads 27″ are shown in theillustrated embodiment). The threads 27″ are elongate, curved elementsthat may be at least partially helically oriented and configured toengage or to be engaged by cooperating features of the plunger 86″ andto cause rotational movement of barrel 20″ relative to the plunger 86″.In one particular embodiment, the threads 27″ protrude from the interiorsurface 23″ into the receptacle 24″ (e.g., as male threads). In anotherparticular embodiment, the threads 27″ extend into the interior surface23″ into the receptacle 24″ (e.g., as female threads).

An embodiment of the plunger 86″ that corresponds to the barrel 20″ mayinclude an engagement feature 87″, such as the depicted notch, thatreceives and cooperates with a corresponding thread 27″, for example amale thread. In some embodiments, the engagement feature 87″ may be aprotrusion which engages and cooperates with a corresponding thread 27″,for example a female thread. In a more specific embodiment, eachengagement feature 87″ is formed in an alignment element 88″ of theplunger 86″. Even more specifically, each engagement feature 87″ may beformed in an edge 89″ of alignment the alignment element 88″(illustrated as an alignment disk) of the plunger 86″. As shown, thealignment element 88″ may be located at a proximal end of the plunger86″ (e.g., the end that will be located closest to an individualoperating a syringe that includes the barrel 20″ and the plunger 86″).Edge 89″ of the alignment element 88″ may abut the interior surface 23″of the barrel 20″ to align the plunger 86″ with the receptacle 24″ ofthe barrel 20″ as the plunger 86″ is forced through the receptacle 24″,along the length of the barrel 20″. As the plunger 86″ is inserted intothe receptacle 24″ of the barrel 20″ and is driven axially along thelength of the barrel 20″, each engagement element 87″ continues toengage its corresponding thread 27″. Due to the helical orientation ofthreads 27″, non-rotational movement of the plunger 86″ along the lengthof the barrel 20″ causes the barrel 20″ to rotate relative to theplunger 86″ as the plunger 86″ is forced through (i.e., into or out of)the receptacle 24″. In the depicted embodiment, movement of the plunger86″ out of the receptacle 24″ (i.e., proximally, toward an individualusing a syringe including the barrel 20″ and the plunger 86″) iseffected as members 82″ and 84″ of handle 80″ are forced together.Members 82″ and 84″ of the handle 80″ may be rotationally joined to eachother at a hinge joint 70″. In one embodiment, the barrel 20″ isrotationally and sealably held within a stationary cylindrical housing40″ which is secured to member 82″ of the handle 80″. The barrel 20″ maybe locked axially within the cylindrical housing 40″ by a snap fit, orother locking means. In another embodiment, the barrel 20″ ispermanently and sealingly bonded within the cylindrical housing 40″ suchthat the barrel 20″ and the cylindrical housing 40″ are configured torotate in unison. In this particular embodiment, the cylindrical housingis rotatably held by the member 82″ of the handle 80″.

Embodiments of syringes with rotatable elements and barrels 20″ thatrotate relative to their plungers 86″ may be used in a variety ofprocedures, including, but not limited to, processes in which material(e.g., biological samples, samples from the body of a subject,aspiration of blood or thrombus/clot, etc.) is removed and/or obtained.

In a biopsy embodiment, a biopsy needle may be rigidly secured to thebarrel 20″, for example at coupling element 28″. The coupling element28″ may comprises a standard luer connector, such as a male luer lockconnector. Movement of the plunger 86″ along the length of the barrel20″ may cause the barrel 20″ and the attached biopsy needle to rotateabout axes extending along their lengths, enabling use of the biopsyneedle in a coring and aspiration technique to manually obtain a sample.A hand held syringe incorporating teachings of the present disclosuremay be advanced and operated manually, even with a single hand, whichmay free the operator's other hand for a variety of purposes, including,without limitation, stabilization of a patient, control of an imagingdevice, such as an ultrasound apparatus, or the like.

In embodiments wherein a catheter is rigidly coupled to a barrel20″(e.g., at the coupling element 28″) that rotates as its correspondingplunger 86″ is driven along its length, actuation of the plunger 86″ mayrotate the catheter about an axis extending along its length, which maybe useful in breaking up or dislodging obstructions, macerating and/orremoving blood clots or thrombi, or in mixing fluids prior to or duringtheir aspiration.

FIG. 37 illustrates an aspiration system 2″ utilizing an embodiment ofthe syringe 10″ which includes a first one-way valve 71″ between theaspiration catheter 73″ and the barrel 20″, which allows flow (forexample of thrombus or blood) from the aspiration lumen 81″ of theaspiration catheter 73″ into the interior of the barrel 20″, in thedirection of arrow B, but does not allow flow in the opposite direction.The flow may travel, for example, into the interior of the barrel 20″during aspiration (e.g., when the members 82″ and 84″ are squeezedtogether). A vacuum source 77″ may be used to collect aspirated material(thrombus, blood, etc.) via an extension tube 75″. FIG. 38 illustrates asystem 3″ including a second one-way valve 79″ within the plunger 86″which allows flow from the interior of the barrel 20″ to the vacuumsource 77″, in the direction of arrow C, but does not allow flow in theopposite direction. The flow may travel, for example, towards the vacuumsource 77″ when the members 82″ and 84″ are released. Both the firstone-way valve 71″ and the second one-way valve 79″ may be incorporatedtogether in either the system 2″ of FIG. 37 or the system 3″ of FIG. 38. A pressure transducer 12 may be used as part of any of the aspirationmonitoring systems described herein to determine the status of theaspiration utilizing the system 2″ or the system 3″. In system 2″ ofFIG. 37 , the pressure transducer 12 is located within the interior ofthe barrel 20″, while in system 3″ of FIG. 38 , the pressure transducer12 is located in-line between the aspiration catheter 73″ and thecoupling element 28″. In some embodiments, the pressure transducer 12may be a separate component that is attached at one end to theaspiration catheter 73″ and at the other end to the coupling element28″. For example, the pressure transducer 12 may be supplied separately,and may be configured for the user to couple to the aspiration catheter73″ and the coupling element 28″ in order to perform a procedure. Insome embodiments, the pressure transducer 12 may be supplied as part ofthe coupling element 28″, and be configured to be attached to theaspiration catheter 73″. In some embodiments, the pressure transducer 12may be supplied as part of the aspiration catheter 73″ and be configuredto be attached to the coupling element 28″. Feedback from the pressuretransducer 12 via the aspiration monitoring system may alert the userwhen to squeeze the members 82″ and 84″, or when to release the members82″ and 84″, or when to replace the vacuum source 77″. For example, theaspiration monitoring system may be configured to alert the user whenthe vacuum has decreased below a threshold, and may send a message tothe user, such as, “squeeze handle.” Additionally, the aspirationmonitoring system may be configured to alert the user when a no-flowcondition is identified, indicating possible clogging, and may send amessage to the user such as “release handle” or “replace syringe.”

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2014/0200483 to Fojtik, published Jul. 17, 2014, whichis incorporated herein by reference in its entirety for all purposes; inaddition, any of the features described herein may be incorporated intoany of the embodiments described in Fojtik, U.S. Patent ApplicationPublication No. 2014/0200483, while remaining within the scope of thepresent disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2004/0116873 to Fojtik, published Jun. 17, 2004, whichis incorporated herein by reference in its entirety for all purposes; inaddition, any of the features described herein may be incorporated intoany of the embodiments described in Fojtik, U.S. Patent ApplicationPublication No. 2004/0116873, while remaining within the scope of thepresent disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2012/0022404 to Fojtik, published Jan. 26, 2012, whichis incorporated herein by reference in its entirety for all purposes; inaddition, any of the features described herein may be incorporated intoany of the embodiments described in Fojtik, U.S. Patent ApplicationPublication No. 2012/0022404, while remaining within the scope of thepresent disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2014/0142594 to Fojtik, published May 22, 2014, which isincorporated herein by reference in its entirety for all purposes; inaddition, any of the features described herein may be incorporated intoany of the embodiments described in Fojtik, U.S. Patent ApplicationPublication No. 2014/0142594, while remaining within the scope of thepresent disclosure.

Any of the embodiments described herein may be used conjunction with anymodel of the Aspire Aspiration Platform syringe (Control MedicalTechnology, LLC, Park City, Utah, USA), having either a rotating barrelor a non-rotating barrel.

In one embodiment, an aspiration system includes an elongate catheterhaving a proximal end and a distal end, the catheter including anaspiration lumen having a proximal end and a distal end, amanually-actuated syringe configured to aspirate liquid, the syringeincluding one or more actuation elements which control the amount ofvacuum applied to the interior of the syringe and a connector configuredfor fluid connection, and a monitoring device including a housing havinga first port adapted for detachable connection to the connector of thesyringe and a second port adapted for detachable connection with thecatheter, a pressure sensor in fluid communication with an interior ofthe housing, a measurement device coupled to the pressure sensor andconfigured for measuring one or more deviations in fluid pressure, and acommunication device coupled to the measurement device and configured togenerate a signal related to a deviation in fluid pressure measured bythe measurement device.

In another embodiment, an aspiration system includes an elongatecatheter having a proximal end and a distal end, the catheter includingan aspiration lumen having a proximal end and a distal end, amanually-actuated syringe configured to aspirate liquid, the syringeincluding one or more actuation elements which control the amount ofvacuum applied to the interior of the syringe and a connector configuredfor fluid connection, and a monitoring device including a pressuresensor in fluid communication with an interior of the syringe, ameasurement device coupled to the pressure sensor and configured formeasuring one or more deviations in fluid pressure, and a communicationdevice coupled to the measurement device and configured to generate asignal related to a deviation in fluid pressure measured by themeasurement device.

An aspiration system 1400 is illustrated in FIG. 39 and comprises anaspiration catheter 1402 that is configured to be deliverable over aguidewire 28. The aspiration catheter 1402 includes a high pressurefluid injection lumen 1404 and an aspiration lumen 1406. The aspirationlumen 1406 extends from the proximal end 1412 of the aspiration catheterto a distal end and is configured to also serve as a guidewire lumen. Afirst y-connector 1410 is coupled to the proximal end 1412 of theaspiration catheter 1402 and communicates with for the high pressurefluid injection lumen 1404 and the aspiration lumen 1406. The highpressure fluid injection lumen 1404 may be configured in a similarmanner to the high pressure fluid injection lumen 536 of the embodimentof FIG. 17 , the injection lumen 1225 of the embodiment of FIG. 18 orthe injection lumen 1257 of FIG. 21 . A sideport 1420 of the firsty-connector 1410 is in fluid communication with the high pressureinjection lumen 1404 and a proximal port 1422 is in fluid communicationwith the aspiration lumen 1406. The first y-connector 1410 may bepermanently attached to the proximal end 1412 of the aspiration catheter1402, or may be connectable to the proximal end 1412, for example, byluer connections. A tubing set 1414 having a cassette 1416 with a piston1418 is configured to be coupled to the sideport 1420 of the firsty-connector 1410, and is also configured to be coupled to and used withthe pump 1254 of FIG. 24 , or other equivalent pumps. The proximal port1422 of the first y-connector 1410 is configured to be coupled to adistal port 1424 of a second y-connector 1426. The proximal port 1422 ofthe first y-connector 1410 and the distal port 1424 of the secondy-connector 1426 may be luer connectors, but alternatively, they may bepermanently connected. Alternatively, the first y-connector 1410 and thesecond y-connector 1426 may be integrally formed, for example byinjection molding or casting. The second y-connector 1426 includes asideport 1428 and a hemostasis valve 1430 (Touhy-Borst, spring-loadedseal, etc.). The hemostasis valve 1430 is configured for sealing overthe guidewire 28 and may be adjustable or actuatable in order to moreeasily move advance and retract the guidewire 28, distally andproximally. The sideport 1428 is configured to couple to a pressuresensor 1432 having a cable 1434 for carrying one or more signals. Thepressure sensor 1432 is configured to interface with the console 1276 ofFIG. 22 or other equivalent consoles. A vacuum source 1436 may becoupled to the sideport 1428/pressure sensor 1432 as described herein.In this particular embodiment, the vacuum source 1436 is syringe. Avalve 1438 is placed in between the vacuum source 1436 and the pressuresensor 1432, in fluid communication with each, and allows the user toopen or close the connection between the vacuum source 1436 and thepressure sensor 1432.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2007/0073233 to Thor et al. (“Thor”) published Mar. 29,2007, which is incorporated herein by reference in its entirety for allpurposes; in addition, any of the features described herein may beincorporated into any of the embodiments described in Thor, whileremaining within the scope of the present disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2001/0051811 to Bonnette et al. (“Bonnette”) publishedDec. 13, 2001, which is incorporated herein by reference in its entiretyfor all purposes; in addition, any of the features described herein maybe incorporated into any of the embodiments described in Bonnette, whileremaining within the scope of the present disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2014/0155931 to Bose et al. (“Bose”) published Jun. 5,2014, which is incorporated herein by reference in its entirety for allpurposes; in addition, any of the features described herein may beincorporated into any of the embodiments described in Bose, whileremaining within the scope of the present disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2010/0204672 to Lockhart et al. (“Lockhart”) publishedAug. 12, 2010, which is incorporated herein by reference in its entiretyfor all purposes; in addition, any of the features described herein maybe incorporated into any of the embodiments described in Lockhart, whileremaining within the scope of the present disclosure.

Any of the embodiments described herein may include some or all featuresof any of the embodiments described in U.S. Patent ApplicationPublication No. 2007/0225739 to Pintor et al. (“Pintor”) published Sep.27, 2007, which is incorporated herein by reference in its entirety forall purposes; in addition, any of the features described herein may beincorporated into any of the embodiments described in Pintor, whileremaining within the scope of the present disclosure.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments may be devised withoutdeparting from the basic scope thereof.

What is claimed is:
 1. A system for real time monitoring of catheteraspiration, comprising: a pressure sensor configured for placement influid communication with a lumen which at least partially includes anaspiration lumen of a catheter, the aspiration lumen configured tocouple to a negative pressure source, the pressure sensor configured tomeasure negative fluid pressure; a processor coupled to the pressuresensor and programmed to measure changes in the negative fluid pressure;and a communication device coupled to the processor and configured togenerate a continuous signal which is characterized by an algorithm thatdepends on measured negative fluid pressure for communicating thechanges in the negative fluid pressure to a user.
 2. The system of claim1, wherein the algorithm is configured such that the continuous signalis generally within a range such that the continuous signal can besensed by the user throughout the range.
 3. The system of claim 2,wherein the continuous signal within the range comprises pitchfrequencies within the human audible range.
 4. The system of claim 2,wherein the continuous signal within the range comprises sound pressureswithin the human tolerance range.
 5. The system of claim 2, wherein thecontinuous signal within the range comprises visible light.
 6. Thesystem of claim 2, wherein the continuous signal within the rangecomprises tactilely sensed vibration.
 7. The system of claim 1, whereinthe continuous signal is proportional to the measured negative fluidpressure.
 8. The system of claim 1, wherein the algorithm dependsdirectly on the measured negative fluid pressure as a variable.
 9. Thesystem of claim 1, wherein the algorithm depends on a difference betweena baseline pressure and the measured negative fluid pressure as avariable.
 10. The system of claim 1, wherein the algorithm depends on anabsolute value of the measured negative fluid pressure as a variable.11. A system for real time monitoring of catheter aspiration,comprising: a pressure sensor configured for placement in fluidcommunication with a lumen which at least partially includes anaspiration lumen of a catheter, the aspiration lumen configured tocouple to a negative pressure source; a processor coupled to thepressure sensor and programmed to measure changes in the fluid pressure;and a communication device coupled to the processor and configured togenerate a continuous signal which is based on an algorithm that variesdepending on the changes in the measured fluid pressure, wherein thecontinuous signal can be sensed real-time by a user for characterizingthe changes in the measured fluid pressure to the user.
 12. The systemof claim 11, wherein the algorithm is configured such that thecontinuous signal is generally within a range such that the continuoussignal can be sensed by the user throughout the range.
 13. The system ofclaim 12, wherein the continuous signal within the range comprises pitchfrequencies within the human audible range.
 14. The system of claim 12,wherein the continuous signal within the range comprises sound pressureswithin the human tolerance range.
 15. The system of claim 12, whereinthe continuous signal within the range comprises visible light.
 16. Thesystem of claim 12, wherein the continuous signal within the rangecomprises tactilely sensed vibration.
 17. The system of claim 11,wherein the continuous signal is proportional to the measured fluidpressure.
 18. The system of claim 11, wherein the algorithm dependsdirectly on the measured fluid pressure as a variable.
 19. The system ofclaim 11, wherein the algorithm depends on a difference between abaseline pressure and the measured fluid pressure as a variable.
 20. Thesystem of claim 11, wherein the algorithm depends on an absolute valueof the measured fluid pressure as a variable.